MorphControl: serialize target list & add minor cleanups

[Ali-RS]

See:
https://hub.jmonkeyengine.org/t/morphcontrol-question/44599?u=ali_rs & #1548 (comment)

[stephengold]

I believe it's unnecessary to serialize the list of targets, since the list will get regenerated by setSpatial() during loading.

[Ali-RS]

I believe it's unnecessary to serialize the list of targets, since the list will get regenerated by setSpatial() during loading.

I was thinking like so but found out setSpatial() is not called when loading from serialized file. You can confirm that by running TestMorph (which uses BinaryExporter.saveAndLoad).

Without serialize the list it will throw

SEVERE: Uncaught exception thrown in Thread[jME3 Main,5,main]
com.jme3.renderer.RendererException: compile error in: ShaderSource[name=Common/MatDefs/Misc/Unshaded.vert, defines, type=Vertex, language=GLSL150]
0:377(9): error: `m_MorphWeights' undeclared

	at com.jme3.renderer.opengl.GLRenderer.updateShaderSourceData(GLRenderer.java:1516)
	at com.jme3.renderer.opengl.GLRenderer.updateShaderData(GLRenderer.java:1543)
	at com.jme3.renderer.opengl.GLRenderer.setShader(GLRenderer.java:1608)
	at com.jme3.material.logic.DefaultTechniqueDefLogic.render(DefaultTechniqueDefLogic.java:96)
	at com.jme3.material.Technique.render(Technique.java:167)
	at com.jme3.material.Material.render(Material.java:1033)
	at com.jme3.renderer.RenderManager.renderGeometry(RenderManager.java:634)
	at com.jme3.renderer.queue.RenderQueue.renderGeometryList(RenderQueue.java:273)
	at com.jme3.renderer.queue.RenderQueue.renderQueue(RenderQueue.java:312)
	at com.jme3.renderer.RenderManager.renderViewPortQueues(RenderManager.java:897)
	at com.jme3.renderer.RenderManager.flushQueue(RenderManager.java:799)
	at com.jme3.renderer.RenderManager.renderViewPort(RenderManager.java:1128)
	at com.jme3.renderer.RenderManager.render(RenderManager.java:1180)
	at com.jme3.app.SimpleApplication.update(SimpleApplication.java:273)
	at com.jme3.system.lwjgl.LwjglAbstractDisplay.runLoop(LwjglAbstractDisplay.java:160)
	at com.jme3.system.lwjgl.LwjglDisplay.runLoop(LwjglDisplay.java:201)
	at com.jme3.system.lwjgl.LwjglAbstractDisplay.run(LwjglAbstractDisplay.java:242)
	at java.lang.Thread.run(Thread.java:748)

or by running TestAnimMorphSerialization.

[stephengold]

Thanks for your latest contribution to JMonkeyEngine!

[Ali-RS]

I appreciate you for reviewing and merging the PR. :)