Adding 'get' command to the CLI, to view a single variable.

This enables the user to type "get variablename" in the CLI, which then shows the value of that variable (or a message saying "Variable 'variablename' not found").
This is easier for the user when they just want to see a single variable, instead of typing 'dump' and then having to parse a big long list of data.  It is also more intuitive than typing 'set variablename', as this feels unsafe.
Bugfix for wrong number of beeps when changing profiles

When changing profiles with the sticks, CleanFlight was beeping 0 times for profile
1, once for profile 2, and twice for profile 3.  This wasn't intuitive, and was
different to how Baseflight beeps when changing profiles.
This change makes baseflight give the same number of beeps as the profile number
that you change into.
Re-use existing code to show all matching cli commands for 'get' instead of exact match.

e.g.  'get deadband' will show all varialbles with the word 'deadband' in it.  exact match only required when setting variables.
Merge branch 'nebbian-feature-cli-get'
Merge pull request #29 from nebbian/feature-change-profile-beep-bugfix

Bugfix for wrong number of beeps when changing profiles
Avoid error message appearing incorrectly after showing cli commands.
Update CLI so that you can dump all, master or profile settings.
Cleanup '...' strings to reduce binary size.  Change version
information.

With this change it's much more obvious what is and what is not included
in a profile.

Examples:

dump
dump profile
dump master
Adding FrSky main battery voltage code back in ('FAS' in telemetry
screen on OpenTX) - it was disabled in baseflight commits
a753661c23c428ede8c2b72e95d3e31f6c8b894e and removed  in
4ae03bb00e5616796989255d4101c4ed51162d50
Latest Naze/Flip32+ binary - many improvements!  Primarily better
Altitude-Hold, Better PPM support.  Sonar alt-hold.  Current sensor
FrSky telemetry.  Cli cleanup (dump profile/master).  Support for SBUS
inverter.  Smaller code size - using GCC Link Time Optimisation and GCC
nano specs.  Updated WS281 LED Support.