CubeBlack-Solo hardware def to use FMUv3 as its parent rather than CubeBlack. Since this older cube doesn't have the same hardware as a new CubeBlack, it is causing conflicts. Nearly everything is the same.
Adds hwdef files for the 3DR Solo. CubeBlack-solo is based on the
CubeBlack hwdef, with the only difference being default parameters
required by the Solo. CubeGreen-solo is is also identical to CubeBlack,
but has default parameters required by those with a Green Cube in their
Solo. Parameter default files are pulled from the Tools\Frame_Parms
directory where the Solo's parameter files are maintained.