Document the various functions and variables used by the current scheduler code.  Includes a rough description of the various priority values stored in struct proc as well as priority propagation.
Document the various functions and variables used by the current
scheduler code.  Includes a rough description of the various priority
values stored in struct proc as well as priority propagation.

Reviewed by:	chris

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase