Move the code from pySim-smpp2sim.py to its own file, so it can be properly
extended.
The current file parses argv, opens a reader and starts the Twisted
reactor at import time, so nothing else can import it.
No functional changes yet, improvements follow in later commits.
Change-Id: Ifd8a15684939977d29ea83a6b669daee14484e88
Eric Wild