jme3-testdata depends on nifty

[stephengold]

The published POM file for "jme3-testdata" indicates dependencies on "nifty-examples" and "nifty-style-black":

<dependency>
<groupId>com.github.nifty-gui</groupId>
<artifactId>nifty-examples</artifactId>
<version>1.4.3</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>com.github.nifty-gui</groupId>
<artifactId>nifty-style-black</artifactId>
<version>1.4.3</version>
<scope>runtime</scope>
</dependency>

"jme3-examples" contains only resources; neither of these is a valid dependency.

This mistake causes "nifty-examples" (20 MBytes) and "nifty-style-black" (74 kBytes) to be unnecessarily incorporated into projects that use "jme3-testdata" (for the Jaime model, for instance) --- even if they don't use Nifty GUI.

• "nifty-style-black" already appears as a dependency of "jme3-niftygui", so the dependency is redundant
• "nifty-examples" is used by "TestNiftyExamples.java" and "TestNiftyToMesh.java" apps in "jme3-examples, so that dependency should be moved from "jme3-testdata" to "jme3-examples"

[stephengold]

I just realized ... due to transitive dependencies, this issue also causes unnecessary incorporation of the "jsr305" (31 kBytes), "nifty" (780 kBytes), "nifty-default-controls" (260 kBytes), and "xpp3" (120 kBytes) jars into projects that don't use Nifty GUI.