Docstrings for modules all over sugar and shell.

These are just the doc strings I created as I was spelunking
through to see how Sugar manages launching applications.  The
resulting auto-documentation is neither polished or finished,
but it should help people reading the code somewhat.

There are a few minor code cleanups:

  * activityhandle (replacing C idiom for initialisation with
    a Python one)
  * bundle registry (using a parameterised directory name so
    that it shows up in the documentation)
  * validate_activity_id function, use isinstance( item, (str,unicode))
    for the query, rather than two separate checks with isinstance

sugar/logger.py

@@ -1,3 +1,4 @@
+"""Logging module configuration for Sugar"""
 # Copyright (C) 2006, Red Hat, Inc.
 #
 # This library is free software; you can redistribute it and/or