add build.properties for app signing.
use ant env
use ant.properties for app signing.
change ndk to r7c to fix native compiling issue.
add missing function impl.
Merge remote-tracking branch 'origin/onyx_eink' into onyx_eink

Conflicts:
	src/org/geometerplus/android/fbreader/ShowDialogMenuAction.java
fix compiling error
modify according changes in OnyxSDK
Merge remote-tracking branch 'origin/onyx_eink' into onyx_eink