Support more drag-n-drop into and out of Playlist.

Fix file manager -> Playlist
Add Recent -> Playlist
Add Playlist -> Player
Add shortcuts x, v, b, esc, up, down, enter, del, 0-9.
Fix pressing Esc changes playlist index.
Make dialogs modal, makes them more Mac-like on OS X.
Make QInputDialog and QMessageBox use sheet style on OS X.
Fix crash or deadlock after calling saveXML().
Add fullscreen toggle action.
Make history view spacing and color consistent with other views.
Tighten spacing and margins in the docks.
Remove toggle state of dock actions in toolbar.

The toggle state looks funny.
Remove Reload button from Encode dock.

We now change the video encode parameters automatically when the MLT
profile changes.
Do not let out point be less than in point.
Fix position and triggering of Fullscreen toolbar action.
Change shortcut for Fullscreen action to be cross-platform.
Update Czech translation.
Fix Encode loading video parameters from preset profile.
Fix playlist playback regression in commit 3423e3.
Fullscreen -> Full Screen
Fix X11 screen capture with audio interpreted as seekable.
Fix automatic video mode for screen capture.