Code cleanup: unused/warnings
Mesh Tool: removes degenerate edges, faces and face ears.
UI: wheel switches tabs over the tab area, or ctrl+wheel anywhere
Sequencer: increase soft limits for translate
Revert 7142b970853f209f6c43319b7f862bcbdbea3728 (transform toggle node hiding)

D187 was committed without review and later rejected by Brecht and myself.
Fix for rare crash in recent mask option to check overlaps
Fix T38664: Blender hang when change scene from script

Deadlock between python script evaluation thread and
drivers evaluation caused by scene update invoked from
ED_screen_set_scene().

Pretty much the same as setting scene current frame
with the same solution BPy_{BEGIN,END}_ALLOW_THREADS.
Fix T38669: Mask duplicate fails with multiple layers

Allow duplicating splines from inactive layers. This way it's
more useful IMO than restricting duplication to an active layer.

TODO: What should be a behavior for clipboard (currently it copies
splines from an active layer only)?
Fix T38670: Mask transform without a movieclip crashes

Disable transform and mask display when there's no active clip.

It's not a matter of returning fallback dimensions if there's no
slip, it's also matter of making it so stabilization and distortion
routines are aware of clip == NULL which is really crappy.

Also almost all the operators are disabled in clip editor without
active clip already anyway.

Also tweaked header UI a bit to not display mask stuff when there's
no active clip,
Bring back mask copy/paste operator to the menu

They got lost in clip interface tab-ilization.
Clear +x flag from source file
Fix for issue in mask overlap with no splines in the mask.
Blender Internal: Revert a part of rB162d6c73e3d0, that broke rendered preview and often causes crash when using material light group.
Fix for another deadlock with py-drivers: BlendData.scene.remove()
Fix T38643: Frame labels are invisible with default theme.

The color for frame labels was a mix of the text color (black by
default) and the node theme color with a factor of 0.8, which
coincidentally is the same as the node body color.

Changed it to 0.4, which is the same as the regular node labels use.
Mask: enable overlap detection by default, more compact buttons
Suppress assert in debug mode.
Fix T38487: Wrapped translate node in combination with other buffered
nodes (Blur) causes crash due to chained read/write buffer operations.

The way read/write buffer operations are created for both the wrapped
translate node and then the "complex" blur node creates a chain of
buffers in the same ExecutionGroup. This leaves the later write buffer
operations without a proper "executor" group and fails on assert.

Solution for now is to check for existing output buffer operations like
it already happens for inputs. This is extremely ugly code, but should
become a lot more transparent after compositor cleanup ({D309}).
Mask: fix for intel openmp which doesn't support casts in for loops
NDOF: default to turntable (blenders default too)