Blender Git Loki

Use pointer for master collection

This allows this pointer to be used, otherwise the pointer is not written

Rename: collections > scene/layer_collections

Read/Write, first take

Fix mistake in last (non-merge) commit

Merge branch 'blender2.8' into workspaces

Make layout template only show layouts of current workspace

Mainly had to do some changes to template_ID to make this work. It now supports setting a custom RNA collection to search the ID's in.

Scale damping by spring length as well

I had forgotten to scale the damping forces...
This made for uneven damping on irregular meshes.

Fix previous error with spring length scaling

Zero-length springs weren't being scaled properly, leading to phantom
forces that introduced rigid-body motion into the simulation.

Implement improved compression model

This implements the Choi and Ko compression model, with an added damping
component, instead of using the same model as for tension, which
improves stability of the internal forces.

Some more comments etc. to AssetEngine API.

Fix objects not disappearing after unlinking collection

Fix bad behavior when switching between asset engines with incompatible paths.

A path valid for a given AE can be invalid with another, we need to
check current path when switching between AEs.

Also do proper check of valid path for Amber engines.

Merge branch 'master' into asset-engine

Make duplicating workspaces work

Fixes for changing layout with workspace

Changing workspace should now change to the active layout of the workspace just fine.
Screen/workspace changing is still a bit hacky since we can't do it during normal handlers. Not sure how we could do it instead, for now I'm just copying hacks from screen changing.

removed high res getter for flags grid

Code clean-up (remove unnecessary struct members and add comments)

Spring forces and jacobians (f, dfdx and dfdv), were unnecessarily being
stored in sring struct. They are only used locally at computation time,
and don't have to remain in memory.

editrestlen was unused.

Fix layout changing when changing workspace

Painfully enhanced columns/rows computation to make best use of available space.

Now layout will use less columns than possible, if it does not increase
number of rows. Allows to fill more evenly available space.

Also fixed some quirks and corner-cases issues.

Fix logical error, in our current UI height is not really adaptative, so we want max to work with heights, not average ones.

Also, add another experimental example of gridflow layout usage (needed
some hacks/tweaks to low-level UI code, by default our buttons tend to
get way to much width than actually needed!).