Added icons for most of the tabs

Implemented a complex mechanism of switching to BTDevicesListFragment only in case BT is enabled
(either initially enabled, or was enabled by the user on the fly)
Encapsulating logic responsible for syncing with device in a separate thread.

Implementing a new protocol which includes a full handshake and packets counting.
Arduino sketch for which mimics momilk device functionality and allows for app's testing
Basic layout for EXTRAS tab + few new graphics