Add support for OGLES20 extension "GL_IMG_texture_npot" in addition to the currently used extension "GL_OES_texture_npot" to detect NPOT support.
Added additional Renderbufferstorage formats for RGB8 and RGBA8 image formats
git-svn-id: https://jmonkeyengine.googlecode.com/svn/trunk@10517 75d07b2b-3a1a-0410-a2c5-0572b91ccdca