Enable TextPainter cache in EFIS.
Optimize HSI and enable TextPainter cache in other widgets.
New TextPainter that uses QPainterPaths for rendering text.
Fix compiler warning.
Use TextPainter everywhere.
More optimizations in EFIS and HSI.

Particularly, remove unnecessary painter saves/restores
and cache painter paths.
Update HSI to paint track with white line instead of dashed yellow.
Scale fonts and pens basing on window size instead of widget size.

This will yield consistent pen width and font sizes
across different instruments.