Updated MetaStation v27G-II.dmm to MetaStation v27G-III.dmm

Updated MetaStation v27G-II.dmm to MetaStation v27G-III.dmm
- Replaced Janitor's Wagon with new Janitor's Cart
- Replaced all station bounced radios with the 'off' variant
- Updated holodeck to be as current main /tg/station
- Fixed broken reference to a data disk on display.
- Compiles again.

Please note that this was a minor bugfix to get the map working again. There is also a much larger overhaul of the map in progress, with many more improvements. Watch this space.

Also I tried to use the map merge tools, it *seemed* to have worked until now. Hrm. Will make sure to get it working next time.