Changed how visibility is handled in a few places to make it more consistent with the new way render data is collected.
Minor warning fix.
Removed abandoned code.
Doc fixes.
Another round of minor fixes to the UI system.  This time focusing on visibility checks and multi-line text layer parsing.
Made several minor touchups to the UI configuration and moved a part of the pause check to the workunit responsible for pausing.  Also the game will remain paused while the options window is open.