Autobuy repair enhancements

[Aingar]

• Now pulls the hull and equipment repair factors directly from common.dll and server.dll respectively
• Now calculates costs for collision group repair
• Minor code cleanup

[Aingar]

Not adding to the patch planning spreadsheet as it's a 'nice to have', only to be worked on after the 'big' stuff is out of the way.

Uploading to make sure it's not forgotten.