Users can select the main unit they want to use now.
Previously the displayed unit always depended on the magnitude of the value.
The old behavior can be restored by switching to the "Adaptive" mode for length, mass and time units.
Meters, kilograms and seconds are the default units for new and old scenes.
The selected unit is also the default unit for user input.
E.g. if cm is selected, whenever the user inputs a unitless number into a field of type length, it will be interpreted as cm.
Reviewer: brecht
Differential: https://developer.blender.org/D3740
This makes the Edit Mesh display settings common to all objects. They can
also be set differently per viewport.
Modifying extra data (seams, sharp edges etc...) will no longer set them
automaticaly visible.
Bumping version because we need to force set all extra draw options for
older files.
