FillBar: auto invalidate when showMinMax is changed
Remove Failsafe codes & complete calibration activity code
FPV like or magnetic compass heading presentation configuration added
Settings: Fixing information on the summary
Merge pull request #496 from arthurbenemann/FPVheading

FPV Heading
MAVLinkParamters: msg.param_index = -1

Reading the GCS_MAVLink.pde - param_index needs to be set to -1 for it
to use ‘param_id’ as name is stirng format
DroneEventsType: Parameter

Add a new event type - PARAMETER
when a parameter is received, registered listeners will be notified
Parameters: Add DroneEvent callback
Parameters: getParameter(String name)

this will search the pamater list andreturn a parameter with the
particular name;
Parameters: getLastParameter()

this will return the last parameter in  the parameter list
CalParamters: using parameters

CalParameters is now using drone.parameters emthod to read single
parameter.
Telemetry Texts Alignment
Default Texts changed to "--"
Little position corrections.
Merge pull request #499 from Paku-/TeleAlign

Telemetry Texts Alignment
Trash button gets red outline
Updated color of flight path,

Fixed Typo, increased default zoom level.
fragment_rx_setup: remove cancel button from main screen
fragment_rc_setup_minmax layout: adding cancel button

changes on the layout to add cancel button and renaming the item
properly
RCSetupFragment: Removing unused code of cancel button
FragmentSetupRCMinMax: Cancel button code implementation