Template for subsurface android package

For modifications to the final source code of built android package
such as permission additions and inclusion of xml and java files, it
is necessary to maintain a template. The template is copied without
any modifications on top of qt android-template before building
subsurface libraries. ( Refer: http://goo.gl/z44dQC )

All android specific files would be added to android subdirectory.

In this commit, permission for usage of USB devices is added to
AndroidManifest.xml. Also included is device_filter.xml. When
devices having VID, PID listed in this file is attached to android,
a dialogbox is displayed asking for permission for subsurface to
use this USB device. Accepting it would take you straight to subsurface
application.

Icons for subsurface and string.xml is included.

Signed-off-by: Venkatesh Shukla <venkatesh.shukla.eee11@iitbhu.ac.in>