* Key.ValidLock: returns whether a lock number is valid (can be unlocked) or belongs to a "does not work" door.
* Key.GetMapColorForLock: returns the automap color for a lock number (or -1 if the lock isn't valid).
* Key.GetMapColorForKey: likewise, but for a specific key.
Due to C++ conversion rules this was a bit too volatile. There's really not enough places where being able to pass a string directly into the sound API was beneficial - the two most frequent functions now got overloaded variants.
* it is now possible to switch back to the main intro loop from the fullscreen console.
* do not distort the background of the fullscreen console. Always draw the console on top of what the main loop currently displays with a translucent black overlay.
* do not use the CONPIC for the fullscreen console as it tends to be more of a distraction than an asset when filling the entire screen.
* cleaned up c_console.cpp and moved several pieces of code unrelated to actual console management out of it.
- added Marisa Kirisame's CHAN_OVERLAP flag.
- exported S_IsActorPlayingSomething to ZScript.
The sound API change required deprecating A_PlaySound and S_Sound. There are now new variants S_StartSound and A_StartSound which have two distinct parameters for channel and flags.
