Fix #34184: cycles speed vector pass should be zero when using motion blur,
instead it had value 10000.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54436 954f8c5b-7b00-dc11-b283-0030488c597c
Fix a few DPI / retina draw issues:

* Color picker cursor was too small, and color cirle was not smooth enough.
* Border select gesture cross before first click did not reach to the border
  of the window.
* Buttons were not drawing emboss properly (also for non-retina actually).
  Note it doesn't draw entirely right for aligned buttons, but this was also
  the case before it got broken.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54437 954f8c5b-7b00-dc11-b283-0030488c597c