Changes to Meteor

- All times are now set in advance. Admins are also made aware of these
times 45 seconds into the round
- Space Weather announcement has 70 % chance of being off by up to 1
minute 30, and 30 % chance of being off by up to 4 minutes
- Shield Gen changed to Shield Projector. Allows to defend space 2 tiles
around it in all directions. Can be deployed in hallways to defend
sudden breaches or in Bar Maint to defend holodeck. Your choice