Add support for ETC1 textures

This is implemented in TP but does not work for AE yet-
I am trying to sort it out.
Merge pull request #181 from nazgee/for-nicolas-ETC1-TP

Add support for ETC1 textures
Updated classpath.
Added clear method to Library.
Minor optimization where using the StringBuilder class.
Added a few more TimeConstants.
Made CatmullRomMoveModifierConfig static.
Minor changes.
Minor changes.
Added SparseLongArray, SparseFloatArray, SparseDoubleArray, SparseByteArray, DoubleArrayLiist, CharArrayList, ByteArrayList, BooleanArrayList. Fixed LongArrayList, IntArrayList. Added SparseArrayUtils.valuesToList and a few more SparseArrayUtils.toString.
Added text/plain MIME type.
Removed a bunch of useless comments.
Added DatabaseUtils.
Minor change.
Fixed typos.
Removed whitespaces.
Formatting.
Added more StrokeFont methods in FontFactory.
Removed usage of FloatMath since it's slower than plain Math since API level 8.
Now allowing EntityLoaders to return null.