Fix DockWidgets on Qt 5.1 for OS X.
Add UI Themes and improve support for HDPI (Retina).
Prevent crashes with no playlist.
Fix default preset for frei0r color grading filter.
Fix crash on White Balance filter with GPU.

And fix temporarily disabling filter when using eye dropper and not GPU.
Make generated XML less verbose.
Fix synchronizing pause between MLT and player.

Conflicts:
	src/mainwindow.cpp
Fix thumbnail creation for Qt5 with GPU.

This actually changes it for non-GPU as well. It has changed from using the producer object to building a new producer based on the resource. This will pave the way for caching the thumbnails keyed on URI and in/out point.
Only handle up/down/numeric keys if playlist open.
Do not let timecodes on scrubbar get too close.
Delete main help page instead of hiding it.
Remove a couple of debug message lines.
Change #frames from 10 to fps on page up/down.