Blender Git Loki

Make Annotations toggleable with main overlay switch

Rename Grease Pencil to Annotation

Some properties and flags are more clear if the name is annotation.

Also changed some text and tooltips.

Merge branch 'blender2.8' into greasepencil-object

User Prefs: Make it clearer which properties affect Annotations only vs GP + Annotations

Annotations: Change default color for new annotation layers

Although we've had a default color for new Grease Pencil layers for
years, hardly anyone ever changed the default color from the old
default of black. This commit changes this default to match the
color used in the annotation pencil icons, giving it a stronger
connection to the tool, and giving users a better default color
that will make the new strokes actually visible with the default
theme.

Annotations: WIP access to tool settings in topbar

Lots of stuff to fix still - Not final UI at all
(in terms of widgets + properties exposed)

What works now:
* Exposed access to the setting controlling the default color to use
when adding new layers
* Exposed access to change which color (layer) and thickness new strokes
get drawn with (as per the current implementation). Now all annotation
tools have tool settings exposed.

Big Todo's:
* Find a way to display color previews of GP Layers as icons
(e.g. how to register all the necessary icon_id's, etc.)
* Replace the prop_search() with an enum prop
* Separate annotation RNA type defines? Context issues? etc.

Cycles: Moved get_aov_rect method to make things easeir for git merge

Annotation Eraser: Only operate on the active layer

Since we aren't exposing per-layer locks here (as we want to avoid
having lots of work enabling/disabling locks), the eraser now only
erases strokes on the active layer

Cleanup: Assorted little tweaks/moving code around

Annotation Eraser Tweaks

* Remove the "soft" modes from the annotation eraser. Now, erasing
strokes will immediately remove the stroke points. This works better
for annotation use cases, as when erasing strokes, you usually just
want to get rid of the notes quickly.

* Show eraser brush size setting in the topbar/tool settings when the
eraser tool is active. (Note: This setting still uses the userpref
setting, which we should move to the scene toolsettings instead
so that it doesn't get reset with each session)

Cleanup: Deduplicate stroke freeing code

Merge branch 'blender2.8' into greasepencil-object

Fix: reorder variable initialization and usage

Fix: X Randomization -> Random X

Fix: set a default brown for Direct coloring

Fix: rename PrincipledHairBsdfNode's melanin stuff

Fix: lower_case OSL variables

Fix: remove random value from closure

Fix: hide Random value if unused

Cleanup