Blender Git Loki

Bugfix: new DPI-controlled UI size code was setting 'view2d re-init'
flag on ED_area_initialize(). This however was causing 2 problems;
- the view state got reset (popping window view back)
- the view2d operator polls failed (sliders didnt work)

This re-init was only needed for the headers though, limiting it
to these types of regions solves it.