Initial commit of morgans spilling algorithm (spill unused values that live through

Initial commit of morgans spilling algorithm (spill unused values that live through
blocks or loops). Other small changes:

* Added some verify functions that check for register pressure or valid schedules (replaces the broken check_pressure in bechordal_main.c)
* Some style/readability improvements to the belady spill code
* Some style/readability improvements to beuses.*
* Fixed registerpressure stat dumper
* Some improvements to bespill.c: When spilling already reloaded values, don't add a 2nd spill.