Major fixes to gles2rice plugin

Fix the following features in gles2rice plugin:
-Multitexturing
-Alpha test
-Fog

TODO on the java side:
- Remove the mipmapping option in "gles2rice settings" has the value is
now hardcoded in the native code.
- Add an option to enable/disable Fog
front: Add option for gles2rice fog effect

Also updated manifest and changelog in preparation for 2.4.0
front: Disable fog effect by default
build: Change version string to debug in manifest
front: Add interface for entering custom polygon offset
Using external coordinate for fog calculation

Fix fog banding issue on some devices.

TODO: Test if fog density is correct on every devices
Merge branch 'master' into lifecycle-fixes

Conflicts:
	src/paulscode/android/mupen64plusae/CoreInterface.java

Manually resolved by moving the following line
   mupen64plus_cfg.put( "Video-Rice", "FogMethod", boolToNum( user.isGles2RiceFogEnabled ) );
from CoreInterface.java (master) to NativeConfigFiles.java (branch).
Merge branch 'master' into lifecycle-fixes

Conflicts:
	src/paulscode/android/mupen64plusae/jni/CoreInterfaceNative.java

Manually resolved by moving CoreInterfaceNative#getCustomPolygonOffset
to NativeImports#getCustomPolygonOffset.

Also required manual rename of variable in MenuActivity from "user" to
"mUserPrefs".
Merge branch 'master' into lifecycle-fixes