onGlitchout event! "glitch" cutscenes!

Just like "sub" cutscenes, now "glitch" cutscenes trigger when the player
hits one of those fancy glitch blocks, before resetting to the start of
the level!
Glitches don't happen near spawn column

Necessitated a little bit of work to allow predictable/retrievable X
starting tile.
Merge pull request #23 from variousauthors/map_glitchout

onGlitchout event! "glitch" cutscenes!