Cleaning up and customizing our frame diff algo.

Frame diff algo now working nicely and providing twice the frame rate.

Pixel diff logic for frame rate improvment now working.
It's still working on a per pixels bases so too slow with full screen update.
Thus it's still disabled.

Trying to optimize our swap buffer implementation by sending only the pixel
block which ave changed. No joy so far.

Restoring some of our on-screen functionality for debug purposes.
We could prove that updating a single pixel is much faster than updating our
whole screen. Single pixel updates runs at full 24 FPS.

Hacking around our UI so that our frame display window remains inside our app.

Adding set pixel method to our QML MiniDisplay.
Adding more metrics and options to our test tab.

Adding MiniDisplay methods to display image and window.
Using our test tab to render our display frame in QML and send it to our display.
Using a timer and frame counter to profile our performance.

Working around our font dialog option listing issues.
Font dialog options are now persisted.
Fixing issue with italic font being cut by using proper string width from boundigRect.

Fixing qml warnings.