Merge pull request #8 from IjonTichy/master

ALTHUD compat, CVar engine rewrite, buncha ZDoom compat shit, new Chroma Storm HUD graphic
Merge pull request #9 from IjonTichy/master

Turns out one last ConsoleCommand was hanging out for ZDoom to get hitch...
Merge pull request #10 from IjonTichy/master

ZDoom is forced to LocalSetMusic for the time being, SetMusicVolume not existing and all.
Merge pull request #11 from IjonTichy/master

[minor] ChromaStormTrail[123] don't exist anymore; remove their gldefs
Replaced GLDefs, slightly sped up Chroma fade to show off the lights, CHROMA now on hud graphic.
Plasma Beam PvE damage slightly lowered, so as to keep from dramatically outshining everything else.
Morph ball space checker don't get blocked by monster lines anymore.
Today I learned about global variables. In singleplayer, weapon spawns for weapons you've already picked up are replaced with missile tanks.
Doom Cannon now uses the ACS missile system. Also its Ready state is rewritten.
Ice Beam now uses ACS missile system
Plasma beam now uses ACS missile system, decorate/beams/common.dec is now a file
Power beam now uses ACS missile system.
Plasma and Spazer Beams now use the ACS missile system.
Merged 478 with the current ENTER script, set MissileAmmo and SuperMissileAmmo as beam ammo types (for althud), reconfigured beam flags, trimmed right-side whitespace
Renamed a few files - I got tired of having tab-completion bring up decaldef.txt when I wanted the decorate/ folder.
Any cheat that gives all weapons now raises your missile count to 255, super missile count to 25, and power bomb count to 5.