Updates to Universal Storage (#9)

Updates as discussed in #9. Integrates my work into RO, including descriptions, oxygen support on the cores, TAC generators, and documentation.

Also updated the Elektron which was consuming only 4 litres per day, as opposed to 24 * 3 per day. (The TAC generator means it will only run as hard as required to keep O2 levels full, and will discard H2 if there's no space for it, just like the ISS!)