BMesh: remove error check on radial loops and consistent naming
BMesh: minor speedup to BM_face_split_edgenet
Fix T40987: Distant Lamps have no influence on Volumes.

Differential Revision: https://developer.blender.org/D639
Followup to rB320b7a59c3eed: also handle background image ID refcount when duplicating/freeing View3D.
Freestyle: minor docstring fixes.
Tooltip improvements for modifier functions
Math Lib: accept a limit of 0.0 when comparing vectors
Math Lib: add compare_len_squared_v3v3 from paint branch
BMesh: avoid redundant normalize comparing angles
Remove redundant NULL check
Tooltip improvements for modifier functions
Py/API: add bmesh.utils.face_split_edgenet
Error in last commit
GHash, EdgeHash: add debugging function to measure the hash quality

Can use to check on improvements to hash functions.
Feature request:

Expose pressure from event system to python. This will return the tablet
pressure, if a tablet is present, or 1.0 if not.
Follow up to previous commit.

* Expose is_tablet property to events to determine if event contains
tablet data.
* Expose tablet tilt for events as a 2D vector in python
Fix T41044 Cycles Bake: world space location affects object space normal pass
BGE: TrackTo actuator: increasing up & track axis options

This is related to Task T34861 to increase up & track axis options for TrackTo actuator. I've just added it to differential to facilitate an easier review.

With the patch applied you can select X, Y and Z axis for the Up axis, and X, Y, Z, -X, -Y and -Z for the track axis.

Related to the implementation I have used the algorithm from Trackto constrain placed in constrain.c but adapted to be used with MOTO library.

The wiki docs are here (http://wiki.blender.org/index.php/User:Lordloki/Doc:2.6/Manual/Game_Engine/Logic/Actuators/Edit_Object#Trackto_Actuator).

Test file is here: {F97623}

I have also uploaded 2 screenshots showing the UI modifications to the TrackTo actuator:

{F91992} {F91990}

Reviewers: moguri, dfelinto

Reviewed By: moguri

CC: Genome36

Differential Revision: https://developer.blender.org/D565
Fix T41074: Several Mouse Look actuators not working well together when reset button are set in one or several of them

Fix provided by lordloki (Jorge Bernal)
Edgehash: Improve magic number for hashing

Gives consistently better results. Tested with wide variety of meshes.