A few fixes and additions to Android build

Fixed missing dependency caused by previous commit, which worked on interpreted mode but failed during compilation (it was missing base-macros, which was required since I replaced a define with define* to be able to use optional parameters).
Added asset processing to Android build.
Disabled parallel compilation in Android build, which was failing randomly for SDL2.
Added utility function to read text files which is portable between host and Android versions (reads from apk/assets using SDL2 RWops).