python: Move various utility classes into a new m5.util package so

they're all in the same place.  This also involves having just one
jobfile.py and moving it into the utils directory to avoid
duplication.  Lots of improvements to the utility as well.

--HG--
rename : src/python/m5/attrdict.py => src/python/m5/util/attrdict.py
rename : util/pbs/jobfile.py => src/python/m5/util/jobfile.py
rename : src/python/m5/util.py => src/python/m5/util/misc.py
rename : src/python/m5/multidict.py => src/python/m5/util/multidict.py
rename : util/stats/orderdict.py => src/python/m5/util/orderdict.py

src/python/m5/main.py

@@ -33,7 +33,7 @@ import os
 import socket
 import sys
 
-from attrdict import attrdict
+from util import attrdict
 import defines
 import traceflags