update README: Google usage statistics is now public beta
(minor) conf should reference python instead of  Pycharm
FIX issue 1: The main program should exit, but remains alive

Because of the thread created by this module, the main program could 
not exit.
Now, this module creates daemons. From the doc:

A thread can be flagged as a “daemon thread”. The significance of this
flag is that the entire Python program exits when only daemon threads
are left. The initial value is inherited from the creating thread. The
flag can be set through the daemon property.

Note Daemon threads are abruptly stopped at shutdown. Their resources
(such as open files, database transactions, etc.) may not be released
properly. If you want your threads to stop gracefully, make them
non-daemonic and use a suitable signalling mechanism such as an Event.