Add Migrate message to L.SubLayouts, for better support of moving windows between groups
Add Migrate message to L.SubLayouts, for better support of moving windows between groups

Ignore-this: d76b2f3e5999999a489b843b4dde59f1

darcs-hash:20090705174934-1499c-b0878bb70fbcdd734deccdc9a6beac9928aded4e

jthornber/XMonadContrib,jthornber/XMonadContrib