Make Separator nodes easier to use

[andydandy74]

• These nodes don't need a sketch plane input (can be derived from the view's plane)
• Lines that aren't located at the same Z should be projected onto the sketchplane

Affected Nodes

• [x] AreaSeparator.FromCurve
• [x] RoomSeparator.FromCurve
• [x] SpaceSeparator.FromCurve

[andydandy74]

Reworked RoomSeparator node still needs testing. This one also counts towards culling nested TurnIntoList nodes...