python: Move more code into m5.util allow SCons to use that code.

Get rid of misc.py and just stick misc things in __init__.py
Move utility functions out of SCons files and into m5.util
Move utility type stuff from m5/__init__.py to m5/util/__init__.py
Remove buildEnv from m5 and allow access only from m5.defines
Rename AddToPath to addToPath while we're moving it to m5.util
Rename read_command to readCommand while we're moving it
Rename compare_versions to compareVersions while we're moving it.

--HG--
rename : src/python/m5/convert.py => src/python/m5/util/convert.py
rename : src/python/m5/smartdict.py => src/python/m5/util/smartdict.py

src/arch/mips/MipsSystem.py

@@ -28,10 +28,10 @@
 #
 # Authors: Jaidev Patwardhan
 
-from m5.SimObject import SimObject
+from m5.defines import buildEnv
 from m5.params import *
 from m5.proxy import *
-from m5 import build_env
+
 from System import System
 
 class MipsSystem(System):
@@ -42,7 +42,7 @@ class MipsSystem(System):
     system_type = Param.UInt64("Type of system we are emulating")
     system_rev = Param.UInt64("Revision of system we are emulating")
 
-if build_env['FULL_SYSTEM']:
+if buildEnv['FULL_SYSTEM']:
     class LinuxMipsSystem(MipsSystem):
         type = 'LinuxMipsSystem'
         system_type = 34