This makes manipulator access closer to operators,
and allows Python access.
This adds RNA for manipulators, but not Python registration yet.
- Split draw style into 2x settings:
`draw_style` (enum) & `draw_options` (enum-flag)
- Rename wmManipulator.properties -> properties_edit,
Use wmManipulator.properties for ID-properties.
Note that this area of the API will need further work since
manipulators now have 2 kinds of properties & API's to access them.
Instead use generic 'WM_manipulator_new', adding a new 'setup'
callback (like wmManipulatorGroup.setup) used to initialize type vars.
This moves conventions closer to wmOperator and simplifies exposing to
Python.
While this is work-in-progress from custom-manipulators branch
its stable so adding into 2.8 so we don't get too much out of sync.
- ManipulatorGroupType's are moved out of the manipulator-map and are now
global (like operators, panels etc) and added into spaces as needed.
Without this all operators that might ever use a manipulator in the 3D
view would be polling the viewport.
- Add optional get/set callbacks for non-RNA properties
Needed so re-usable manipulators can control values that
don't correspond to a single properly or need conversion.
- Fix divide by zero bug in arrow manipulator (when moving zero pixels).
