Added bluetooth checks on UseBluetooth

Added permissions for Bluetooth in manifest.
Added checks in UseBluetooth for:
1. Presence of bluetooth adapter on device
2. Bluetooth is enabled or not
If either of the above conditions are not satisfied. The activity
finishes returning to Home activity.
No useful stuff happens in UseBluetooth activity yet.
Theme is changed to Sherlock light with Dark ActionBar.

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