INT E0 - ConcCP/MConcurrent CP/M by Digital Research, now DR Multiuser DOS,DR Multiuser DOS - "P_PRIORITY" - SET PROCESS PRIORITY
	CL = 91h
	DL = new priority (00h highest to FFh lowest)
Return: nothing
Notes:	sets priority of calling process; transient processes are initialized
	  to priority C8h
	also supported by REAL/32
SeeAlso: INT E0/CL=8Eh