Pie Menus C code backend.

This commit merges the code in the pie-menu branch.

As per decisions taken the last few days, there are no pie menus
included and there will be an official add-on including overrides of
some keys with pie menus. However, people will now be able to use the
new code in python.

Full Documentation is in http://wiki.blender.org/index.php/Dev:Ref/

Thanks:
Campbell Barton, Dalai Felinto and Ton Roosendaal for the code review
and design comments

Jonathan Williamson, Pawel Lyczkowski, Pablo Vazquez among others for
suggestions during the development.

Special Thanks to Sean Olson, for his support, suggestions, testing and
merciless bugging so that I would finish the pie menu code. Without him
we wouldn't be here. Also to the rest of the developers of the original
python add-on, Patrick Moore and Dan Eicher and finally to Matt Ebb, who
did the research and first implementation and whose code I used to get
started.
Minor cleanup
Manifest used to be installed on non-windows platforms
Fix T40744: MIP Map is generating strange noise in texture, Blender Internal
Fix T40203: Fluid simulation needs more memory than displayed.

Nothing like a fix, actually, this is an issue in elbeem afaik.
For now, just warn user that complex obstacles may breack things.
Fix T40047: Smoke: Maximum value for initial velocity.

Based on D644, by robschia (Roberto Schiavone).
Fix for previous commit - after talk with physics guys (Genscher, Miikah), better
to keep soft UI limits as is, and only raise hard ones.
Fix T41360: Crash on Boolean Modifier

The issue was caused by the wrong attributes maps in certain
circumstances after union intersections.

Namely issue might have happen when more than one iteration of
union was happening and it was caused by the fact that new faces
might be allocated on the same address as freed face from the
old mesh.

Didn't find a nicer fix for this apart from correcting the whole
attributes map after each union step.

We could try removing attributes for the meshes which are getting
deleted, but in asymptotic it's gonna to give exactly the same
complexity as the current approach.
Fix compilation error with debug scons

The issue is that we've got hell with DEBUG and _DEBUG,
theu're defined really inconsistent acros CMake and SCons.

Used more reliable NDEBUG definition for IDP_spit.
Fix T41362: CPU and GPU rendering gives different results

We can't really make CPU and GPU results look the same in all possible
circumstances, but here we can make them look close enough to each other
by making it so sobol pattern for bounce number is the smae for both
CPU and GPU.

This makes CPU and GPU render results look the same with low number of
samples, high number of samples was never an issue.
Fix T41403: Grid Particles only partially generated.

Getting dominant axis (biggest dimension of bbox) was wrong, now using BLI code for that.
Fix marker selection margin ignoring DPI
Fix uninitialized memory use
Spelling
Proof-of-concept implementation of Freestyle support for Cycles.
Initial implementation of Cycles materials for Freestyle stroke rendering.
Added debug prints.
Removed ad-hoc use of R_PERSISTENT_DATA for Freestyle/Cycles.
Fix for nested Cycles sessions.
Fix for hard-coded #include file paths.