share/png: add Android specific makefiles to the png library

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
lib: intro the android implementation of mnit

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
lib: import the android module from mnit_android

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
nitg/android: add a deeper folder to generated project

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
nitg/android: compile with the png lib

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
nitg/android: load assets on the APK

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
example: update mnit examples with android version

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>