barrier/notes

throw specs:
  must add XThread if method can be cancelled
  must add out-of-memory exception if method allocs and returns an object
    should catch and handle out-of-mem if object wasn't going to be returned

CServer
 * must have connection thread in screen info map
    allows disconnect if screen map changes and screen is removed
 * put mutex locks wherever necessary (like accessing m_active)
 * must handle disconnect of screen by warping cursor off of it

CClient
 * need methods for screen event handler to call as appropriate

threads and X:
  X doesn't handle threading very well.  need to ensure that all X
  calls are protected by a mutex.

server						client
------						------
[accept]			<--		connect
challenge			-->		[encrypt]
[verify]			<--		response (encrypted challenge, client name)
hangup if invalid
query info			-->		
					<--		info (size)

...
enter (x,y)			-->
clipboard data		-->									optional
mouse/key events	-->									optional
query clipboard		-->									optional
					<--		clipboard data					(cont.)
leave				-->

...
grab clipboard		-->

... (on clipboard ownership stolen)
					<--		clipboard lost

... (on screen resize)
					<--		info (size)

... (on screen saver, primary screen)
saver (on/off)		-->

...
quit				-->
					<--		close

---
primary screen
	open
	close
	enter
	leave
	warp
	clipboard (get/set)
	screen saver (show/hide)
	queue events with server (including screen saver activation)

secondary screen
	open
	close
	enter
	leave
	warp
	synth mouse
	synth key
	clipboard (get/set)
	screen saver (show/hide)
	queue events with client (clipboard lost/changed, size change)

---
client:
	open
	close
	wait: server messages, clipboard taken, screen resize, quit

server:
	accept
		asynchronously accept new clients
	config
		asynchronously accept and handle config message (via HTTP)
	primary
		asynchronously handle primary screen events
	comm
		send/recv messages to/from clients