* Add a file header with some information

* Delete the DelaySlotInfo objects created by the SchedulingManager class.
  These leaked objects were accounting for 3/4 of the memory leaked by the
  backend, so this is a relatively major win.
* Reorganize SchedulingManager::getDelaySlotInfoForInstr so that it has
  better code locality (making it easier to read).

llvm-svn: 2197