Final cleanup before merge into wiggly-widgets branch

Optimize transform manipulator drawing a bit more

Avoid unnecessary operations on each redraw, also avoid ugly variable caching in RegionView3D struct memory.

Cleanup: Remove tmp functions added for work on this branch

And some other minor cleanup

Port VSE widgets to new update system

Those were the last remaining widgets. Almost done with this branch :)

Adjustments to make object widgets work with update tagging system

Object widgets are still unfinished and it's uncertain if they'll stay though.

Port node editor backdrop widget to new update tagging system

Merge branch 'wiggly-widgets' into temp_widgets_update_tagging

Merge branch 'master' into wiggly-widgets

Conflicts:
release/scripts/startup/bl_ui/properties_data_bone.py
source/blender/blenloader/intern/versioning_270.c
source/blender/editors/include/ED_transform.h
source/blender/editors/transform/transform.c
source/blender/makesdna/DNA_armature_types.h

Add missing refresh tag on screen layout change

Correction to previous commit.

Port UV transform manipulator to new update system

Greatly reduces number of operatations happening on re-draw.

Add/use typedefs for function pointers

Merge branch 'wiggly-widgets' into temp_widgets_update_tagging

Did some minor adjustments for changes from wiggly-widgets to fit this branch.
Conflicts:
source/blender/windowmanager/widgets/WM_widget_api.h
source/blender/windowmanager/widgets/WM_widget_types.h
source/blender/windowmanager/widgets/intern/wm_widgetgroup.c

Add/use typedefs for function pointers

Correct include guard, remove unnecessary include and struct declarations

Correct comments on header usage.

Minor cleanup for previous commit

Port graph editor backdrop widget to new update system

Merge branch 'wiggly-widgets' into temp_widgets_update_tagging

Fix DNA alignment error on 32 bit systems