Added preferences for RC screen
Now the user can:
*select between mode 1 and 2
*reverse each channel
*choose if throttle should return to center or not
Merge pull request #200 from realbuxtehuder/RCScreen

Added preferences for RC screen
Preference for QuickModeButtons mode
Extend the SettingsActivity to show the current prefernce values
Merge pull request #202 from realbuxtehuder/RCScreen

    Preference for the QuickButtons
Preparing for release 0.11.3