Changed hydro trays, fertilizer and syringes over to use the reagent procs.

Conflicts:
	code/game/machinery/biogenerator.dm
	code/modules/clothing/suits/jobs.dm
	code/modules/reagents/Chemistry-Reagents.dm
	code/modules/reagents/reagent_containers/glass.dm
	maps/tgstation2.dmm
Reapplying some fixes that I think DM may have saved over, whoops.
Adjusted process_reagents() so hydro trays are refillable with water and nurients when the tray is dead/empty.
Adjusted gas exude code.

Conflicts:
	code/game/machinery/hydroponics.dm