Update README

Update the readme to refer to the diydrones location.
Param Write UI confirmation

Add logic to provide a visual confirmation of parameters
written to the UAV when the "Write" button is clicked.

Also, display a count of parameter differences between
the current settings and a just-loaded file.

Also changed the highlight color in the grid slightly to
make it easier to see the values when using the indoor
mission style theme.
Use C++ style cast instead of C-style
Merge branch 'master' of https://github.com/diydrones/apm_planner

Conflicts:
	src/ui/configuration/AdvParameterList.cc