This PR makes the 'convert rooms' button permanently on the toolbar and accessible whichever node is selected, so you can convert rooms without having to select the RoomManager first.
It also adds a togglable item 'view portal culling' to the 'View' menu which is a simple way of setting the RoomManager 'active' setting without the RoomManager being the selected node.
Both of these have keyboard shortcuts, which should make it much faster to reconvert rooms and edit.
In addition there the string in the 'Perspective' Listbox is modified to show [portals active] when portal culling is operational, for visual feedback. This is updated when you change modes, and when the rooms are invalidated.
When using the preview camera feature it turns out as well as culling the game objects, this also culls the editor gizmos from the preview camera, which makes the editor hard to use in this mode.
To get around this problem we simply disable frustum culling for GLOBAL portal_mode objects when in preview camera mode. This could be a bit slower in an editor scene with lots of gizmos but is the simplest way of solving the problem.
Portal margins were not being correctly sent to the PortalRenderer from the SceneTree, so all margins were being used as default (1.0). This PR fixes this.
It turned out the new autolinking feature was linking portals AFTER the static meshes had been added to rooms in the PortalRenderer. This meant that large meshes weren't being sprawled across these portals. The fix involves doing the autolinking BEFORE adding the static meshes.
Fixes a bug in the warning for portals being in the wrong direction, they should have only been checkout for outgoing portals. This was resulting in erroneous warnings.
Also the room conversion logs are refined to be more compact and informative.
A warning icon is also added in the gizmo for portals where autolink fails.
