Improved packet decoding to acquire RR information, updated UI to include stubbed HR and Signal pages.

* Added RR acquisition; handles overflow.
* Added page handling for ANT+ packets; obtaining manufacturer ID, etc.
* Created stubs for the HR Data and Signal Data pages.
* Using ViewFlipper to navigate the page layouts via HeartRateMonitorActivity.
* Back button correctly handles the displayed page according to the FSM (including returning to Android "home").

Signed-off-by: Adam Thwaites <thwaites.adam@gmail.com>