Renaming widget to AttitudeIndicator (Q* is typically for classes in the Qt API)
Switching to normalized coordinate system, simpler tick mark selection
Rendering steps separated into individual methods
Pitch indicator lines with text markings
Heading indicators, backing cache

Using a QPixmap backing cache for proper clipping.
It will also enable supersampling which provides smoother text
rendering.
Using the property/event system to cause cache updates
Enabling font scaling when widget resizes
Slightly safer property set methods
Initialize yaw value and don't provide keypressevent method
Switch back to MainWindow implementation and use property system to update widget
Enabling 2x supersampling for prettier rendering

(On by default)
Keep heading information in the view at extremes
Modify default settings, remove unused enums
Updated Readme, project file