Blender Git Loki

Draw Manager: Fix multiple timer query issued for one pass.

Cycles: Implement denoising option for reducing noise in the rendered image

This commit contains the first part of the new Cycles denoising option,
which filters the resulting image using information gathered during rendering
to get rid of noise while preserving visual features as well as possible.

To use the option, enable it in the render layer options. The default settings
fit a wide range of scenes, but the user can tweak individual settings to
control the tradeoff between a noise-free image, image details, and calculation
time.

Note that the denoiser may still change in the future and that some features
are not implemented yet. The most important missing feature is animation
denoising, which uses information from multiple frames at once to produce a
flicker-free and smoother result. These features will be added in the future.

Finally, thanks to all the people who supported this project:

- Google (through the GSoC) and Theory Studios for sponsoring the development
- The authors of the papers I used for implementing the denoiser (more details
on them will be included in the technical docs)
- The other Cycles devs for feedback on the code, especially Sergey for
mentoring the GSoC project and Brecht for the code review!
- And of course the users who helped with testing, reported bugs and things
that could and/or should work better!

Fix unfreed render-layer properties memory after loading file

Would cause pointer to allocated memory to be overridden.
Steps to recreate were:
* Start Blender
* Save
* Open saved .blend
* Close Blender -> should report unfreed memory

Cleanup: use index syntax instead of addition

Harmless but made accessing the first element read strangely.

Cleanup: use uint/ushort for polyfill2d

Cleanup: use const pointers where possible

Fix PyAPI crash assigning/deleting id-properties

Caused by D113.

Merge branch 'master' into blender2.8

Cleanup: unused return, redundant assignments

PyAPI: Remove bpy.app.handlers.scene_update

This is routinely mis-used to continuously run scripts,
causing performance problems.

This should be replaced with more specific handlers, or possibly timers.
See: T47811

Cleanup: naming

bmesh: use 'uint' instead of 'unsigned int'

no functional changes.

Cleanup: line length, use const struct members

Add missing weight paint vertex shader

Fix all objects being selected when opening pre-2.80 files

Caused by rBe87ddda149b. Selecting objects shouldn't be done in such a
low level function anyway (IMHO).
Made sure duplicating objects still works correctly.

Pass selection to weight paint vert overlay instead of colors

Update paint wire when changing modes

Implement overridable scene render settings

This add a new set of (possible) render settings that can be defined at
the scene level and overridable at the scene layer level.

Once we get workspaces we can either add workspace inbetween scene and
scene layer evaluation. Or to replace layer settings, to avoid extra
confusion to users.

An example of this setting is "samples", as implemented now for the clay
engine.

Fix crash with no active object

Cycles: Fix access array index of -1 in SSS and volume split kernels