Fix T63648: Missing update when changing particle force fields

Force fields requires relations update in the dependency graph.

Cleanup: Remove dead code

There is no more sorting happening, so the comment is out of date
by manu reasons. If something extra is needed there it would need
to be done differently anyway.

Cleanup: Remove unneeded texture nodes update function

The function was calling update() on the time curve, but there
is no update callback on that node. So, effectively the function
was doing nothing.

Cleanup: Remove unneeded compositor update function

Similar to previous commit.

Compositing with animation on socket values and image sequences
still works fine.

Cleanup: Remove image preview code

Was commented out for literally 10 years.

Fix T63590: Blender crashes when deleting particle hair keys

Disable clang-format for Libmv

This is an odd-ball: it's a library which has own style and
guidelines, and just happened to be developed by Blender developers
and also happened to rely on some functionality of intern/ for its
C-API.

Might consider using Google's clang-format in the future (this is
what the style is supposed to be in this library).

Fix compilation error when using SDL dynamic loading

Merge branch 'blender2.7'

Buildbot: Attempt to fix wrong branch in buildinfo

For some reason the buildinfo header was not re-generated. The root
reason is not really clear to me, so simply remove the header similar
to the CMake cache.