Updated Catalyst for older cards from 12.6 to 13.1

Updated Catalyst for older cards from 12.6 to 13.1 and added "Legacy" in front for clarification. The Catalyst 13.1 legacy driver also supports the the necessary extensions for Team Fortress 2 so it should be the recommended driver.
Merge pull request #1108 from bootkiller/patch-1

Updated Catalyst for older cards from 12.6 to 13.1, change accepted