Gradle, Shader fixes and naming conventions

Hi,

first of all this adds a gradle build, like jme uses for the next releases.
-> Removed redundant folder
-> Moved sources to src/main/java as is the default for maven and gradle
-> added assets as a ressource folder
-> renamed packages to comply to http://docs.oracle.com/javase/tutorial/java/package/namingpkgs.html

second it fixes 2 shader related parts, one using a unnecessary high GLSL level, the other being a out unifrom that was never written two. With these changes it is possible to run it even on an Intel Onboard (HD 4000) so pretty much everywhere.