Point 2.73a release to updated addons revision

Show 'a' on the splash screen

Point addons to the backported revision

Bugfix T43293: Crash when editing shared GPencil datablock in VSE

The problem here was that when a Grease Pencil datablock is shared between
the 3D view and another one of the editors, all the strokes were getting handled
by the editing operators, even if those strokes could not be displayed/used
in that context. As a result, the coordinate conversion methods would fail,
as some of the needed data would not be set.

The fix here involves not including any offending strokes in such cases...

Conflicts:
source/blender/editors/gpencil/gpencil_edit.c

Fix error in freestyle api

Fix own error in freestyle api

Conflicts:
source/blender/freestyle/intern/python/BPy_ViewShape.cpp

Sequencer: Don't crash when trying to rebuild proxy without having sequence edits

Fix T43301: Three of the 'mirror keyframes' tools were mirroring along wrong axis.

Names are rather confusing here... :/

SDL wrangler: Support loading SDL2 libraries of different names

Seems different distros might have different naming rules, so need
to adopt our code for that.

Fix T43156: Cycles incorrect final render, proper viewport with moblur disabled

Really stupid issue caused by typo in bitfield bit lead to bit conflict,

Not sure how it was done, could be some bad merge conflict resolve in the
original commit or just pure man stupidnes.

This is a nice example when having set of small test render scenes hooked
to the ctest would really help.

It's probably not that stopper issue (even tho still quite bad) since it
was made 2 months ago. But if we ever do 'a' this time it's a nice change
to include.

Fix T43311: using displacement shader crashes blender

Issue was caused by wrong order of scene device update, which could
lead to missing object flags in shader kernel.

This patch solves a bit more than that making sure objects flags are
always properly updated, so adding/removing volume BSDF will properly
reflect on viewport where camera might become being in volume and so.

Fix for security issue loading blend's

Auto-Execute option could be overridden by opening a startup.blend

Fix OpenGL Context freeing

Fix for regression in bmesh connect-pair

T42563 fix wasn't right, fortunately this doesn't fail in most cases.

Fix typo in OCIO configuration file

Fix T43204: Shrinkwrap constraint, project mode: Space ignored in bone case.

Own fault in rBb154aa8c060a60d to fix T42447... Reverted that commit, and added
kind of not-so-nice hack instead.

Note root of the issue comes from the special case we are doing here re 'Local'
space of parent-less objects. In that case, local space should be the same as
world one, but instead we apply the object rotation to it... This is inconsistent
with all other cases and could very well lead to other issues as T42447, but afraid
fixing that properly would be rather hairy - not to mention it would likely break
all existing riggings etc. :(

Should be safe for a 2.73a, shall we need it.

Fix T43208 material flickering in edit mode.

Happens because material setting now occurs in the derived mesh drawing
routine as it should. However that means that it also happens during
selection and that influenced the drawing state somehow.

In 2.72 this did not occur because material setting happened during draw
setting (skip or draw) instead of after the draw setting passed (so
selection would skip it by use another draw setting function). Of course
this violated design but worked.

Made it now so backbuffer selection does not enable materials (it's
redundant in those cases anyway).

This could be ported to a possible 'a' release but as is classic with
display code there may be some other places that it could backfire.

Tested fix with texture/vertex painting and selection which use
backbuffer for both subsurf and regular meshes and it seems to work OK.

Fix T43229: Knife-project regression (broke knife-project)

There have been quite a few issues with knife precision,
tested reports (T43229, T42864, T42459, T41164) and this works with all.

BMesh: Tweak behavior for select more/less

Stepping over faces gives overall nice results but it stopped wire edges from working.
Now step over wire too.

Fix invalid memory access in gradient brushes - could cause a crash in
MacOS.

This looks like an oldie and should not influence release, but if we do
make an 'a' build it's safe to include.

Report by Craig Jones, thanks!