Blender Git Loki

Fix: Sequencer timecodes was using wrong properties

- The Start value and the Playhead value both used 'frame_start', which only tells you where the strip was originally inserted. Instead 'frame_final_start' is now used, which results in the correct timeline values.
- When scaling the sidebar some of the the labels weren't scaling correctly, this has been fixed
- Use Hold Cut/Cut instead of Hard/Soft Cut, for consistency

Patch by Peter Fog

Differential revision: https://developer.blender.org/D5065