SCIENCE! Update:

- More R&D stuff. Moved code from code/datums/technology to code/game/research (more apt and it isn't JUST datums now). Still very WIP.
- Circuit printer now requires Sulfuric Acid instead of H2SO4. (Yes, I get the irony)
- New helper proc: between(low, middle, high). It returns middle unless it is greater than high (in which case, it returns high) or less than low (in which case it returns low). It's a fairly simple proc but it cleans up some bits of code I am working on.
- Changeling chem regeneration is now a curve rather then a flat amount. At low amounts (<20) it's faster then in r917, at high amounts it's slower (>20). This means you can use cheap abilities more often and expensive abilities less.
- Changeling "Dart" abilities now named "sting" abilities to (Hopefully) cause less confusion. "Boost Dart Range" renamed "Ranged Sting."
- Changeling "Absorb DNA" ability now not only doesn't cost chem to use, it actually regenerates a small amount (if successful).

git-svn-id: http://tgstation13.googlecode.com/svn/trunk@929 316c924e-a436-60f5-8080-3fe189b3f50e

code/game/master_controller.dm

@@ -78,7 +78,7 @@ datum/controller/game_controller
 				M.Life()
 			if (M.mind)
 				if (M.mind.special_role == "Changeling")
-					M.chem_charges = max(min((M.chem_charges+0.25), 50), 0)
+					M.chem_charges = between(0, (max((0.9 - (M.chem_charges / 50)), 0.1) + M.chem_charges), 50)
 		sleep(-1)
 
 		for(var/datum/disease/D in active_diseases)