BMesh: add BM_vert_splice_check_double

checks if splicing verts creates duplicate edges
Cleanup: assert / warn
BMesh: intersect tool

Modeling tool to cut intersections into geometry (like boolean, without calculating inside/outside).
Faces are split along intersections, leaving new edges selected.

Access from Face menu.
Fix T41314: OpenGL error when using Cycles engine
Fix for line style shader/texture types showing up in the node editor when Freestyle is disabled at compile time.

Problem report by Thomas Dinges on IRC, thanks!
Fix T41085: Blender crashes when using "spline" or "segments" for bevel curve factor.

Root of the issue goes to the fact that bevel list calculation might drop some points
if they're at the same position. This made spline length calculation goes wrong.

Now the length of the bevel segments is stored in the bevel list, so values are
always reliable.

Initial patch by Lukas Treyer with some tweaks from me.
Correction to the mipmaps generation

Seem we've always were wrong with multiplying alpha by 255,
other channels seems to be multiplied by 256 with the shift
operations.
Fix T41462: "Reload from trusted" button not prompting for confirmation.

Made 'revert_mainfile' op also handle the 'use scripts' option, and use it
for this feature (since it has a nice simple invoke confirmation popup).
Fix T41426: floating menus - scroll issues.

Do not reset active but if cursor is not over it when getting mousewheel events.
Fix T41474: Second renderlayer doesnt render if first one has 'Use Surfaces' disabled
Install_deps: Better handling of 'check installed' in Debian, and fix jack2d check.

Patch D742, by oweissbarth (Oliver Weissbarth), thanks!
Fix T41137: Old render result from viewport render in camera view does not go away when middle clicking
De-duplicate EWA filter code between renderer and compositor

The title says it all, move the EWA filter to BLI (currently it's
math_interp.c) and use the function from both BI renderer and the
compositor.

This makes more central place of the algorithm, allowing to have
fixes and optimizaitons synchronized across the two usages.

This also fixes T41440: Displacement in compositing creates holes

Reviewers: campbellbarton, lukastoenne

Reviewed By: lukastoenne

Maniphest Tasks: T41440

Differential Revision: https://developer.blender.org/D748
Fix building on some compilers (clang on OSX).

Reported and patch by jensverwiebe (jens verwiebe).
Fix T40653: Modified keymap: MMB not behaving like RMB?

Modal frame_change was not terminating on mmb release event...
Fix T39630: Mouse Wheel doesn't detect Multi Window Focus
Correction to previous curve bevlist commit
Fix T41456: soft light texture blend mode zero effect

Soft light and Linear light blend modes weren't implemented in glsl

Reviewers: psy-fi

Maniphest Tasks: T41456

Differential Revision: https://developer.blender.org/D744
Fix for fix (don't guess enum's sign)
Fix for BKE_deform_flip_side_name getting fooled by extra separator characters

D740 by ldo with own edits