Room modes and undo handling
@sbanca - thinking about undo. Maybe we offer "room modes":
1. Free for all: Everyone can modify everyone's work. No undo
2. Layer per user: Users work on their own layer. Undo works on their own changes
3. View-only: Only the room owner can draw. Undo works
4. Owner undo: Everyone can modify everything but only the owner has undo
Not sure if the last one is worth adding - but it naturally falls out of the other modes. There might be other combinations I haven't thought of.
1. Free for all: Everyone can modify everyone's work. No undo
2. Layer per user: Users work on their own layer. Undo works on their own changes
3. View-only: Only the room owner can draw. Undo works
4. Owner undo: Everyone can modify everything but only the owner has undo
Not sure if the last one is worth adding - but it naturally falls out of the other modes. There might be other combinations I haven't thought of.
