[MAP] DNA scanner pods now open and close like crates. This has fixed the foll...

...owing:

*Resolves #252 - Contents of dna scanners will be ex_acted properly.
*Resolves #125 - Mobs chestbursting in the scanner pod will no longer cause issues with entering/exiting the pod. The larva will be able to slither out (assuming it isn't locked), upon which the icon_state will update. Or it may be opened externally in a similar fashion.
*Items are no longer lost inside scanner pods when a mob is inside the pod with items and it mutates into a monkey or something.
*There are no longer any restrictions on having inorganic items on mobs being scanned.

Special thanks to Cheridan for the sprite-changes.

Modified   code/game/dna.dm
Modified   icons/obj/Cryogenic2.dmi

![sprites](http://i.imgur.com/Gv3Sig5.png)