X.A.SpawnOn: add docs
X.A.SpawnOn: add docs

Add more documentation, including documentation from
X.U.SpawnOnWorkspace by Daniel Schoepe.

darcs-hash:20090204102424-3ebed-b91defc4d2c2736838f75d2ee7e9f98005903d27

jthornber/XMonadContrib,jthornber/XMonadContrib