Mipmapped texture arrays

Fixed TextureUtil to properly handle mipmapped texture 2d arrays and 3d textures
Merge pull request #128 from GreenCubes/patch-1

 * Fix issue where using a texture array with pregenerated mipmaps would fail with a GL error.
 * Remove references to esoteric EXT_abgr and EXT_bgra extensions entirely, which might even be causing issues on some systems, instead replaced with standard OpenGL 1.2 constants
 * ARGB8 and BGRA8 formats now support sRGB -> linear conversion if sRGB pipeline is used, previously they were ignored.
 * All float and half float formats are considered supported if we either support OpenGL 3 or ARB float texture.
 * Cleanup TextureUtil a bit by removing constant references from ARBHalfFloatPixel, ARBTextureFloat, EXTPackedFloat, EXTTextureSharedExponent and EXTTextureSRGB to GL21 and GL30 classes (which are identical anyway).
 * Check if we support sRGB textures before choosing sRGB format (although this check should have been done earlier? not sure..)
Merge branch 'master' of github.com:jMonkeyEngine/jmonkeyengine
 * More sanity checking when enabling sRGB pipeline, to ensure its actually supported before calling any sRGB related functions. Also provide more log messages if something is odd or goes wrong.
 * Remove the sanity check from TextureUtil since it is now done once during initialization of the renderer.
 * If LwjglRenderer.VALIDATE_SHADER is enabled, log shader compilation warnings as Level.WARNING instead of Level.FINE. Also slightly better grammar in shader compile / link messages.
SDK:
- fix recognition of boolean properties is/set pattern
.gitignore : simplify + ignore private
Revert ".gitignore : simplify + ignore private"

This reverts commit 0e5e58a1f87dd6f2feea6cc1366c681129b55358.
gitignore: add explicit list of private files to ignore
gitignore: ignore directory instead of files
SDK: fix JmeGenericControl to display initial value of Property and inherited Property (grouped by class)
Merge pull request #142 from davidB/wip_sdk_properties_control

SDK: fix JmeGenericControl to display initial value of Property and inhe...
Merge pull request #141 from davidB/wip_scenecomposer

.gitignore : simplify + ignore private
SDK: fix NPE in JmeGeometry.propertyChange
Merge pull request #143 from davidB/fix_npe

SDK: fix NPE in JmeGeometry.propertyChange
Merge pull request #2 from jMonkeyEngine/master

merge with jmonkeyengine master