Building jME-SDK issues

I’m trying to build the latest SDK/Engine from the Master Branch. I forked the SDK project on GitHub, and cloned it locally. Then I checked out the master branch (of the SDK). When I try to build with, “gradlew buildSDK” I receive the following:

gbutler@gbutler-Bonobo-Extreme:~/netbeans/Git/sdk$ ./gradlew buildSdk
Full Version: 3.1-1665
POM Version: 3.1.0-SNAPSHOT
NBM Revision: 1665
NBM UC Suffix: nightly/3.1/plugins

FAILURE: Build failed with an exception.

* Where:
Build file '/mnt/userspace/gbutler/netbeans/Git/sdk/build.gradle' line: 141

* What went wrong:
A problem occurred evaluating root project 'sdk'.
> Could not resolve all dependencies for configuration ':corelibs'.
   > Could not find org.jmonkeyengine:jme3-jogg:3.1.0-SNAPSHOT.
     Searched in the following locations:
         file:/home/gbutler/.m2/repository/org/jmonkeyengine/jme3-jogg/3.1.0-SNAPSHOT/maven-metadata.xml
         file:/home/gbutler/.m2/repository/org/jmonkeyengine/jme3-jogg/3.1.0-SNAPSHOT/jme3-jogg-3.1.0-SNAPSHOT.pom
         file:/home/gbutler/.m2/repository/org/jmonkeyengine/jme3-jogg/3.1.0-SNAPSHOT/jme3-jogg-3.1.0-SNAPSHOT.jar
         http://jcenter.bintray.com/org/jmonkeyengine/jme3-jogg/3.1.0-SNAPSHOT/maven-metadata.xml
         http://jcenter.bintray.com/org/jmonkeyengine/jme3-jogg/3.1.0-SNAPSHOT/jme3-jogg-3.1.0-SNAPSHOT.pom
         http://jcenter.bintray.com/org/jmonkeyengine/jme3-jogg/3.1.0-SNAPSHOT/jme3-jogg-3.1.0-SNAPSHOT.jar
         http://updates.jmonkeyengine.org/maven/org/jmonkeyengine/jme3-jogg/3.1.0-SNAPSHOT/maven-metadata.xml
         http://updates.jmonkeyengine.org/maven/org/jmonkeyengine/jme3-jogg/3.1.0-SNAPSHOT/jme3-jogg-3.1.0-SNAPSHOT.pom
         http://updates.jmonkeyengine.org/maven/org/jmonkeyengine/jme3-jogg/3.1.0-SNAPSHOT/jme3-jogg-3.1.0-SNAPSHOT.jar
         http://nifty-gui.sourceforge.net/nifty-maven-repo/org/jmonkeyengine/jme3-jogg/3.1.0-SNAPSHOT/maven-metadata.xml
         http://nifty-gui.sourceforge.net/nifty-maven-repo/org/jmonkeyengine/jme3-jogg/3.1.0-SNAPSHOT/jme3-jogg-3.1.0-SNAPSHOT.pom
         http://nifty-gui.sourceforge.net/nifty-maven-repo/org/jmonkeyengine/jme3-jogg/3.1.0-SNAPSHOT/jme3-jogg-3.1.0-SNAPSHOT.jar
         https://jitpack.io/org/jmonkeyengine/jme3-jogg/3.1.0-SNAPSHOT/maven-metadata.xml
         https://jitpack.io/org/jmonkeyengine/jme3-jogg/3.1.0-SNAPSHOT/jme3-jogg-3.1.0-SNAPSHOT.pom
         https://jitpack.io/org/jmonkeyengine/jme3-jogg/3.1.0-SNAPSHOT/jme3-jogg-3.1.0-SNAPSHOT.jar
     Required by:
         :sdk:unspecified
   > Could not find org.jmonkeyengine:jme3-networking:3.1.0-SNAPSHOT.
     Searched in the following locations:
         file:/home/gbutler/.m2/repository/org/jmonkeyengine/jme3-networking/3.1.0-SNAPSHOT/maven-metadata.xml
         file:/home/gbutler/.m2/repository/org/jmonkeyengine/jme3-networking/3.1.0-SNAPSHOT/jme3-networking-3.1.0-SNAPSHOT.pom
         file:/home/gbutler/.m2/repository/org/jmonkeyengine/jme3-networking/3.1.0-SNAPSHOT/jme3-networking-3.1.0-SNAPSHOT.jar
         http://jcenter.bintray.com/org/jmonkeyengine/jme3-networking/3.1.0-SNAPSHOT/maven-metadata.xml
         http://jcenter.bintray.com/org/jmonkeyengine/jme3-networking/3.1.0-SNAPSHOT/jme3-networking-3.1.0-SNAPSHOT.pom
         http://jcenter.bintray.com/org/jmonkeyengine/jme3-networking/3.1.0-SNAPSHOT/jme3-networking-3.1.0-SNAPSHOT.jar
         http://updates.jmonkeyengine.org/maven/org/jmonkeyengine/jme3-networking/3.1.0-SNAPSHOT/maven-metadata.xml
         http://updates.jmonkeyengine.org/maven/org/jmonkeyengine/jme3-networking/3.1.0-SNAPSHOT/jme3-networking-3.1.0-SNAPSHOT.pom
         http://updates.jmonkeyengine.org/maven/org/jmonkeyengine/jme3-networking/3.1.0-SNAPSHOT/jme3-networking-3.1.0-SNAPSHOT.jar
         http://nifty-gui.sourceforge.net/nifty-maven-repo/org/jmonkeyengine/jme3-networking/3.1.0-SNAPSHOT/maven-metadata.xml
         http://nifty-gui.sourceforge.net/nifty-maven-repo/org/jmonkeyengine/jme3-networking/3.1.0-SNAPSHOT/jme3-networking-3.1.0-SNAPSHOT.pom
         http://nifty-gui.sourceforge.net/nifty-maven-repo/org/jmonkeyengine/jme3-networking/3.1.0-SNAPSHOT/jme3-networking-3.1.0-SNAPSHOT.jar
         https://jitpack.io/org/jmonkeyengine/jme3-networking/3.1.0-SNAPSHOT/maven-metadata.xml
         https://jitpack.io/org/jmonkeyengine/jme3-networking/3.1.0-SNAPSHOT/jme3-networking-3.1.0-SNAPSHOT.pom
         https://jitpack.io/org/jmonkeyengine/jme3-networking/3.1.0-SNAPSHOT/jme3-networking-3.1.0-SNAPSHOT.jar
     Required by:
         :sdk:unspecified
   > Could not find org.jmonkeyengine:jme3-niftygui:3.1.0-SNAPSHOT.
     Searched in the following locations:
         file:/home/gbutler/.m2/repository/org/jmonkeyengine/jme3-niftygui/3.1.0-SNAPSHOT/maven-metadata.xml
         file:/home/gbutler/.m2/repository/org/jmonkeyengine/jme3-niftygui/3.1.0-SNAPSHOT/jme3-niftygui-3.1.0-SNAPSHOT.pom
         file:/home/gbutler/.m2/repository/org/jmonkeyengine/jme3-niftygui/3.1.0-SNAPSHOT/jme3-niftygui-3.1.0-SNAPSHOT.jar
         http://jcenter.bintray.com/org/jmonkeyengine/jme3-niftygui/3.1.0-SNAPSHOT/maven-metadata.xml
         http://jcenter.bintray.com/org/jmonkeyengine/jme3-niftygui/3.1.0-SNAPSHOT/jme3-niftygui-3.1.0-SNAPSHOT.pom
         http://jcenter.bintray.com/org/jmonkeyengine/jme3-niftygui/3.1.0-SNAPSHOT/jme3-niftygui-3.1.0-SNAPSHOT.jar
         http://updates.jmonkeyengine.org/maven/org/jmonkeyengine/jme3-niftygui/3.1.0-SNAPSHOT/maven-metadata.xml
         http://updates.jmonkeyengine.org/maven/org/jmonkeyengine/jme3-niftygui/3.1.0-SNAPSHOT/jme3-niftygui-3.1.0-SNAPSHOT.pom
         http://updates.jmonkeyengine.org/maven/org/jmonkeyengine/jme3-niftygui/3.1.0-SNAPSHOT/jme3-niftygui-3.1.0-SNAPSHOT.jar
         http://nifty-gui.sourceforge.net/nifty-maven-repo/org/jmonkeyengine/jme3-niftygui/3.1.0-SNAPSHOT/maven-metadata.xml
         http://nifty-gui.sourceforge.net/nifty-maven-repo/org/jmonkeyengine/jme3-niftygui/3.1.0-SNAPSHOT/jme3-niftygui-3.1.0-SNAPSHOT.pom
         http://nifty-gui.sourceforge.net/nifty-maven-repo/org/jmonkeyengine/jme3-niftygui/3.1.0-SNAPSHOT/jme3-niftygui-3.1.0-SNAPSHOT.jar
         https://jitpack.io/org/jmonkeyengine/jme3-niftygui/3.1.0-SNAPSHOT/maven-metadata.xml
         https://jitpack.io/org/jmonkeyengine/jme3-niftygui/3.1.0-SNAPSHOT/jme3-niftygui-3.1.0-SNAPSHOT.pom
         https://jitpack.io/org/jmonkeyengine/jme3-niftygui/3.1.0-SNAPSHOT/jme3-niftygui-3.1.0-SNAPSHOT.jar
     Required by:
         :sdk:unspecified

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED

Total time: 21.036 secs
gbutler@gbutler-Bonobo-Extreme:~/netbeans/Git/sdk$ 

Should I be trying to use a different value for this?

ext.jmeEngineVersion = "3.1.0-SNAPSHOT"