Fixed a bug in ManhattanHeuristic.
Merge pull request #246 from nicolasgramlich/patch-1

Fixed a bug in ManhattanHeuristic.
Fixed wrong calculation in Texture.getTextureMemorySize().

Was massively overreporting (64x). =/

Thanks to @yukuku .
Fixed typo.
Added donation section in README.md.
Update README.md
Added tip4commit to README.
Merge branch 'GLES2-AnchorCenter', remote-tracking branch 'upstream/GLES2-AnchorCenter' into GLES2-AnchorCenter