Preparing for Droidplanner v0.3.1 realease.
Fix typo error
Starting to implement RC control via GCS.

Works on CH0 and CH1 but must be refactored, and finished.
Enable and disable overide functions.
Moving RcOutput class to it's on file.Also renames PID Activity to RC.
Improving the Enable and Disabling of the RC control.
Improving Channel Mapping.
Adding a Joystick Widget.
Organizing widgets.
Changing Joystick widget event to use a flot in the -1..1 range.
Add a function to check the connected input devices.
Improving the RC activity layout.
Merge pull request #28 from arthurbenemann/joystick

RC control (issue #25)
Preparing for release v0.4.0