Messing around with Meteor values

- Meteors now last one hour from shuttle call. Still shorter than your
average round if antag taxi doesn't happen too easy
- Meteor density has been reduced a little bit in an attempt to reduce
the lag
- Removing a var that was being set every tick to try and de-clutter
everything

Massive optimizations will likely be needed to make Meteors less
lag-apocalyptic, but this should set everything on the right way