Began work on TextureAtlas support for BitmapFontLoader

-Added a field to the BitmapFontParameter
-Improved documentation a bit
Added support for BitmapFontLoader to load regions from TextureAtlases

-Not tested!
More support for loading BitmapFonts from atlases
Added a test for this PR
Added a test for proper disposal of resources
Added the resources for the BitmapFontAtlasRegionTest
Removed dependencies on the original font images

-Whoops, they shouldn't have been there in the first place
Merge branch 'bitmap-font-loader-texture-atlas' of https://github.com/JesseTG/libgdx into JesseTG-bitmap-font-loader-texture-atlas
fixed up BitmapFontLoader PR
Merge branch 'JesseTG-bitmap-font-loader-texture-atlas'
updated CHANGES