[PATCH wayland v3] protocol: Add minimize/maximize protocol

[Bill Spitzak]

The underlying problem is that if a window is full-screen or maximized, 
and you minimize it, then un-minimize should put it back to full-screen 
or maximized. Thus un-minimize cannot be the "normal" state.

The compositor could track the previous state and set that but then the 
client can't change the previous state while minimized.

The proposed "un-minimize request" means the compositor does not know 
what state will result after the un-minimize.

I think this can be solved by merging all these states into a single 
integer as bits:

	MAXIMIZED = 1;
	FULL_SCREEN = 2;
	MINIMIZED = 4;
	...

The rules are that if MINIMIZED is on then it is minimized, and the 
other bits are ignored. If not then FULL_SCREEN is on it is fullscreen 
and MAXIMIZED is ignored. Etc.

The compositor can send an event to a surface saying that the state 
should change to a new set of values. Un-minimize just means it turns 
off the minimize bit and sends the new value.

The client can send commands changing the state of surfaces. If it wants 
to turn off maximize while minimized, it just turns off the bit.

This has a number of advantages:

  1. greatly reduces the api count

  2. Easy to add some new "state" to existing shell api

  3. All plausable implementations of clients and shells I can think of 
would end up storing a set of flags just like this anyway and tracking 
the state.