Blender Git Loki

UI: Clean up Sequencer/Preview Menu and Preview Menu

The Sequencer/Preview Menu is a mixture of both the Sequencer and the Preview menu functions, but they are currently not presented in an organized way.

Moved the Preview Zoom functions up next to the Sequencer Zoom functions with a separator in between.
Moved the Preview Show functions up next to the Sequencer Show functions with a separator in between.
Uncommented Show Framenumber Indicator, since it does not work or have a function after scrubbing in the timebar was implemented.
Renamed Show Metadata to Show Image Metadata, since it does only show metadata for images.
Added Show Annotations to View Menu for consistency.
Added Frame Overlay to View Menu for consistency.
Added Fractional Zoom to a sub-menu, since Sequencer/Preview View menu became too long. This sub-menu is in consistency with the Fractional Zoom menu in the Image Editor.
In Sequencer/Preview mode the Fractional Zoom will be named Fractional Preview Zoom, to specify that this function is only for the Preview.

Patch by Peter Fog (tintwotin)

Differential Revision: https://developer.blender.org/D5339