Fix crash on exit due to recent MLT opengl change.
Let drag to another track left of origin trim in.
Add split to timeline clip menu.

Use new join function for undoing a split to also fix undoing an insert
edit.
Revert "Fix crash on exit due to recent MLT opengl change."

This reverts commit 56ddbe5c56d2808db7e04b42501bf9d802301063.
Only set m_lastFrame if not using GPU.
Set default locale from system or selected language.

This will make numeric real controls use locale radix instead of always
dot.
Show some numerics using locale.
Add Restore Layout and Show Title Bars to View menu.
Forgot to add cpp file to previous commit.
Fix crash on startup on Windows with dock title bars hidden.
Add Show Toolbar to View menu.
Fix composite adding black bars to lower layer.
Fix non-fill composite mode with GPU processing.
Add using a system monitor for external preview.
Add shortcuts to tooltips and use different icon for lift.
Update English translation.
Save track height and timeline zoom in project XML.
Switch from videostab2 to vidstab filter.
Update stabilize filter to match MLT change to store results in a file
Add audio loudness filter