Use default font wherever possible. Where that doesn’t work, use
ScreenTools::dpiAdjustPointSize.

More consistent with Qml usage pattern

Also many LinkManager API changes to further isolate all link
management inside LinkManager.

Switch QGC firmware upgrader for PX4 to AWS and Travis. Use beta/stable/master for Firmware, map all three items to master for Flow (because there are not beta/stable branches)

Also turn them back on

These tests that make direct calls into the tool bar need to be updated.

No longer buttons so switch to Rectangle for cleaner Qml

- Much simpler UI
- MVC style qml programming model

- Updated MainWindowTest to catch this problem
- Also implemented initial pass at SetupView unit test

- Updated MainWindowTest to catch this problem
- Also implemented initial pass at SetupView unit test

Fixes Issue #1162

UAS may be around at constructor time