Entering unknown command in qdb client break command-processing loop

[GoogleCodeExporter]

If I connect the qdb command line client (i.e. by running "python -m qdb") to a 
qdb server, it seems to get confused when I enter an unknown command. For 
example, if I enter "cont" instead of "continue", I get this:

----

abingham@achewood% python3 -m qdb             ~/projects/qdb.el (git)-[master] 
qdb debugger fronted: waiting for connection to ('localhost', 6000)
running   test.py 
 > test.py(1)
-> import cmd
 (Cmd) cont
*** Unknown command:  cont

----

And the client will just sit there without providing a new prompt until I press 
control-c. I've debugged this a bit and the client seems to be waiting for a 
response or message from the server. 

I'm developing an emacs extension to use qdb, and this behavior makes it 
difficult to interact with qdb since the extension looks for the (Cmd) prompt 
as the key for parsing qdb output.

Original issue reported on code.google.com by austin.bingham on 17 Nov 2013 at 8:39