ruby: Working M5 interface and updated Ruby interface.

This changeset also includes a lot of work from Derek Hower <drh5@cs.wisc.edu>

RubyMemory is now both a driver for Ruby and a port for M5.  Changed
makeRequest/hitCallback interface. Brought packets (superficially)
into the sequencer. Modified tester infrastructure to be packet based.
and Ruby can be used together through the example ruby_se.py
script. SPARC parallel applications work, and the timing *seems* right
from combined M5/Ruby debug traces. To run,
% build/ALPHA_SE/m5.debug configs/example/ruby_se.py -c
  tests/test-progs/hello/bin/alpha/linux/hello -n 4 -t

src/mem/SConscript

@@ -32,8 +32,9 @@ Import('*')
 
 SimObject('Bridge.py')
 SimObject('Bus.py')
-SimObject('PhysicalMemory.py')
 SimObject('MemObject.py')
+SimObject('PhysicalMemory.py')
+SimObject('RubyMemory.py')
 
 Source('bridge.cc')
 Source('bus.cc')
@@ -44,6 +45,7 @@ Source('physical.cc')
 Source('port.cc')
 Source('tport.cc')
 Source('mport.cc')
+Source('rubymem.cc')
 
 if env['FULL_SYSTEM']:
     Source('vport.cc')