Last fix wasn't complete, sorry for that..
Aaaarh! aaargh!
Pie menus:

If user drags away from initial position, menu changes to drag style and
returning to that position won't remake the menu click-style. Allows to
use the threshold indicator to cancel the pie.
Cycles: Avoid segment NULL check, we access it before this function already.
Cycles: Avoid intermediate function when we sample all lamps.
Switch sampler icon to the right, it's easier for artists to access.
Cleanup: typos and extra brackets.
Cycles: Optimization for Heterogeneous Volume Shadows.

* Don't compute expf() for every step, instead sum the intermediate values and calculate it every N (8 for now) steps. This helps a few percent (~5% on a cube with wave texture) in my tests here.
Cycles: Optimize Equi-Angular sampling using binary range search.

Patch by Lukas Tönne and myself.
Fix 'quick smoke' not rendering anything (texture coordinates was left unset)

Not quite sure why default did not work here, might need further investigation.
Cycles: Don't check closure flag in kernel_volume_decoupled_scatter(), we check this before the function already.
UI: avoid spacetype and butspacetype mismatch
Fix T41435: Info-text lags changing space-types
Cleanup: comment & var name
ColorRamp HSV, HSL Blend Modes

D297 by charlie with own edits
Fix T41443: Separate bug with Curves & Hooks

This solves the crash, but indices might be wrong after the separation.

There are loads of other ways to confuse hook indices in both meshes and
curves, for now considering this a TODO.
Modifiers: consider all constructive modifiers as 'preview' ones as well.

Indeed, constructive modifiers are highly likely to modify CDLayers like vgroups or vcols!

See vertexgroup2.blend file ({F93770}) in T40523, especially obvious with subsurf modifier.
Solidify Modifier "Rim Only" Option

D737 by scorpion81 with own edits
Revert "Fix T41222 Blender gives weird output when baking (4096*4096) resolution on GPU"

This reverts commit a48b372b04421b00644a0660bfdf42229b5ffceb.

Leaving only the part that fix device_multi.cpp
Final Fix T41222 Blender gives weird ouput when baking (4096*4096) resolution on GPU

It now uses the tile size to split the job. For CPU this may add
overhead, but for GPU this is highly needed.

Reviewers: sergey

Differential Revision: https://developer.blender.org/D690