- Bad to remove proc file now, even though it's nearly useless. Reinstated
  in the name of compatibility. 

- Restored original semantics - if software_suspend() is enabled, then just
  call that (and never go into low-power state). Otherwise, call acpi_suspend().

- acpi_suspend() is simply a wrapper for pm_suspend(), passing down the right
  argument. This is so we don't have to do everything manually anymore.

- Fixed long-standing bug by checking for "4b" in string written in to 
  determine if we want to enter S4bios.