Add known traps & search for traps when waiting

For traps that might be invisible to the PC, create a copy of the trap definition with visibility set to 0 and prefix the trap id with "known_"
Use those traps instead of the normal ones when placing a (otherwise invisible) trap
When waiting a turn, search the surroundings for traps, and if possible make them into the known_ ones so they stay visible.
Merge remote-tracking branch 'BevapDin/traps-the-second' into FrankenMod