Atmospheric maintenance room added to virology & reflowing of it's piping.

I closed the previous pull request because it had several annoying flaws and connecting virology was a stupid idea.
So i came back to my initial plan to put air system in virology back in the hands of atmo.

I nudged the south airlock two tiles down and enlarged one side of the window by one tile to be able to pass the disposal pipes around the room.

Before:
![image](https://f.cloud.github.com/assets/598409/1524071/a8c62c14-4bc0-11e3-8969-ce6e28f8699c.png)

After:
![image](https://f.cloud.github.com/assets/598409/1524077/b39bdac6-4bc0-11e3-8446-c9c6dea285b3.png)

I think it adds a nice little vulnerability to virology by allowing misuse of gasses to some degree, but not to the point where the AI can just turn it into an incinerator on command. Virology being kind of a little bunker, this makes it depend a little more on atmo and increase the likelihood of virology requiring an eventual canister refill (why bother having a fully simulated life support system on the station if sectors aren't even using it right?). Due to monkey vent crawling we cannot connect to the station, so this is the next best thing.