CubeSolo variant of the FMUv3

The CubeSolo build is based on FMUv3, but includes a large set of default parameters required by the Solo. Among many other things, this does include the slew rate limiting for protecting the Solo's ESCs.

For the parameter list used by this build, see Tools/Fram_params/Solo_Copter-3.7_BlackCube.param

Using this build in waf

./waf configure --board CubeSolo
./waf copter
The completed firmware binary will be located in /ardupilot/build/CubeSolo/bin/arducopter.apj