closed #2469：LabelTest and TileMapTest crash on windows.
closed #2434: simply Android.mk
Merge pull request #3356 from dumganhar/iss2469-windows-path2

closed 2469：LabelTest and TileMapTest crash on windows.
closed #2434:fixed path
Merge pull request #3355 from minggo/iss2434-refactor_androidmk

closed #2434: simply Android.mk
update s3tc#1