Adds the ability to inject chemicals into the atmospherics pipeline thro...

...ugh the following methods:

* Inject into canister and release
* Inject into canister and hook into a loop
* Inject into canister and transfer into an internals tank
* Inject into canister and share between canisters

Adds an industrial sized 'injector' to the atmospherics closets to facilitate dispersion of chemicals into the air-stream.

Plasma, Fuel and Thermite in the air will add to the flammability of the air, but not neccesarily ignite it.

99.5% of chemicals can be dispersed, and will react as intended, including viruses, acid, slime toxin, alcohol etc.
* A known "issue", but not exactly an issue, is that explosive reactions (EMP,Potassium etc) will be small.
I used 500 because I like round numbers. Also I wasn't sure what to base it on that wouldn't allow stupid amounts of reagents.