Adding Olimexino notes and details of the Olimexino Shield V1 (by
Dominic Clifton)
Replace cli command gps_initial_baudrate_index with gps_baudrate.

The index is not really a user concern and leads to confusion.  gps
baudrate is not set like any other baud date and the determination of an
appropriate index is hidden from the user.

If the user specifies a baudrate that is not supported the default index
is used which is current the index for 115200.

This also allows GPS to work on softserial ports at up to 19200.
Add whitespace to ChebuzzF3 notes.
Updating Olimexino board documentation to cover new HoTT telemetry port.
Latest binaries
Add RSSI PWM on CH2 input.

Also support FrSky 1khz RSSI.  See documentation also added in this
commit.

This commit also cleans up the PWM mapping code.  'mask' didn't need to
be a mask and it wasn't possible to add another 'type' since there were
only 4 possible values when it was a mask and they were already defined.  
Combined with switching to using 16 bits instead of 8 for the mapping
configurations, it's now possible to have 256 types instead of 4 at the
expense of a few bytes of flash.

Moved the RSSI calculation into rx_common.c, previously it was in the
main loop.