Fix issue in fullscreen patch.

Don't change old event codes! Keymap diffing depends on those being the
same across versions to work.
Complementary fix for rB8054372: Follow the common naming scheme by
using negate_mat3_m4 instead of negate_m4.

This avoids changing the behavior and only flips the 3x3 part of the
matrix.
Add a few more warnings so coders hopefully will take note that event
codes get stored in keymaps and should not be changed
Fix project-file generators (didn't close files)
Libmv: Initial commit of unfinished AutoTrack API

This starts the creating the new AutoTrack API. The new API will
make it possible for libmv to do full autotracking, including
predictive tracking and also support multiple motion models (3D
planes etc).

The first goal (not in this patch) is to convert Blender to use
the new API without adding any new functionality.

This API currently contanins:

- Frame accessor to access frames which are stored in Blender side.
- New Tracks implementation
- New Reconstruction implementation

Currently this API only tested on doing the same frame-to-frame
tracking as the old API allowed to do. But it also supports now
predictive tracking which is based on the Kalman filter.
Libmv: Add autotrack API to the C-API

Pretty much straightforward changes, nothing to be mentioned specially.
Libmv: Replace region tracker with autotracker in Blender

The title actually tells it all, this commit switches Blender to use the new
autotrack API from Libmv.

From the user point of view it means that prediction model is now used when
tracking which gives really nice results.

All the other changes are not really visible for users, those are just frame
accessors, caches and so for the new API.
Libmv: Support disabled color channels in tracking settings

This was never ported to a new tracking pipeline and now it's done using
FrameAccessor::Transform routines. Quite striaghtforward, but i've changed
order of grayscale conversion in blender side with call of transform callback.

This way it's much easier to perform rescaling in libmv side.
Fix T42431 lagging on texture painting.

Issue here is that seam outset was being calculated wrong and as a
result we filled too many unneeded pixels. Code can be improved here by
clamping perhaps but left it as is for now. Thanks to Campbell for the
help resolving this!
Remove leftover error prints.
Cleanup: use function to calc shell thickness
View3d - walk: expose gravity toggle to keymap
Revert "Scons/funstuff: notify when the binaries are compiled"

This reverts commit cdf53701599ace0b3410cbb75b0313bd969c417c.

Please always keep build-systems simple, boring & functional,
anyone who liked notification popups can write a simple build script.
Fix T42447: Shrinkwrap constraint: mismatch in handling sclaing in projection case.

Constraint space conversion ignores object scale, which is OK in most cases. But here,
we are converting a normal from world to local space, and when later converting it
into target space to actually do the BVH raycast, we use TransformSpace which
does applies objects' scaling to normals, as expected.

Best solution here is to also take object's scale into account when converting
from local to world space.
Fix T42401: Gaussian blur node is visibly squared-off at larger sizes

The root of the issue comes to the way how we sample the gaussian filter in
RE_filter_value(). We need to scale x to -3*sigma..3*sigma segment in order
to get the whole bell.

The old code tried to do it, but failed dramatically, plus it used some weird
gaussian sampling formula. Replaced it with much more clear one, which gives
proper blur now.

There's no visible different in AA sampling in BI render tho.

Other filters like Mitchell still tends to give wrong square shaped blurs,
but they're much more difficult to resolve because they're just wrong in
the code -- for some reason smaller kernel size means more blur. Let's solve
this later.
Fix T42344: EWA filter produces blured results

Derivatives variable names are swapped in the old EWA filter code,
need to adjust for that.

TODO: Make naming fore clear in there.
Fix T42277: Apply track's mask on displaying preview not working
Texture Paint Add Simple UVs:

Add simple uvs now does a cube unwrap and pack operation. Result is not
optimal by far but it should not result in crashes and it will be quite
usable for simple cases.
Fix T42391: HSV correction shader node gives negative values

This mainly happens when over-saturating already saturated color.
After some discussion with Campbell and loads of tests we decided
to clamp the result RGB color. As an alternative we might want to
clamp corrected HSV values instead, but that would lead to some
larger changes in the render results.

TODO: The same is to be done for compositor nodes.
Compositor: Don't let HSV correction to output negative colors