config: Add hooks to enable new config sys

config: Add hooks to enable new config sys

This patch adds helper functions to SimObject.py, params.py and
simulate.py to enable the new configuration system.  Functions like
enumerateParams() in SimObject lets the config system auto-generate
command line options for simobjects to be modified on the command
line.

Params in params.py have __call__() added
to their definition to allow the argparse module to use them
as a type to check command input is in the proper format.