Outliner: Includes cleanup

Merge branch 'master' into soc-2019-outliner

Merge branch 'master' into soc-2019-outliner

Outliner: increase contrast of selected and active highlights

Outliner: Don't allow duplicates for merge search

Only show one item for each subtree element in a merge search popup.
Selecting an element from the popup that has multiple instances in the
subtree will select the first instance in the tree.

Outliner: Clear dirty flag after sync from outliner

This prevents syncing to the outliner on draw which deselects
non-syncable data like mesh data and collections.

Outliner: Activate on range select with no active element

If no active element exists in the outliner, activate the cursor
element instead of only selecting.

Outliner: Remove parent set popup menu for specific types

Removes the popup for setting the parent to curves, lattices, and
armatures. It makes more sense from an outliner perspective to set
the parent to objects only.

Outliner: Openclose fixes

Remove walk in / walk out support for walk navigation. Now left
and right arrow keys only close and open outliner element subtrees.

Fix click+drag on disclosure triangles not behaving as expected.
Now the dragged elements will be either opened or closed, using the
state of the first click+dragged element.

Outliner: Don't sync outliner selection to other outliners

Outliner: Sync select toggle tweaks

Move the toggle lower in the popover as this toggle is not as
important. Also use a checkbox rather than button.

The toggle is still drawn as a button with an icon when the outliner
is in sequence display mode, as the filter popover is not drawn
in that mode.

Merge branch 'master' into soc-2019-outliner

Outliner: Use GSet for select sync from outliner

Outliner: Comments cleanup

Outliner: Fix selection syncing for edit bones

Fixes selection syncing from outliner for edit bones not tagging
for updates.

Outliner: Fix selection syncing of linked items

When an item was linked to multiple collections, an outliner select
would sync the selection state of the last instance, deselecting
even if a previous element was selected.

Selection syncing from the outliner now maintains lists of selected
objects and bones to prevent syncing errors.

Outliner: Use interaction mode to restrict syncing

Use the current interation mode to prevent syncing from getting out
of sync. Because the bone elements shown in object mode are not the
same elemens as in pose or edit mode, it is necessary to only sync
bones in bone edit or pose mode.

Outliner: Deselect data elements on selection sync

Outliner items like mesh data and collections cannot be synced
to the 3D view, but it is still useful to have them selected in
the outliner. When syncing selection to the outliner, it makes
sense to deselect these data elements.

Outliner: Comment and includes cleanup

Merge branch 'master' into soc-2019-outliner