debug flag in Ext.rpc can now be a function, which will receive the RPC object.
Rarely usefull, but still interesting if you're testing a lot.
Updated a variable name to fit into PEP8
Ext.use debug parameter default value added
Added exempt=True parameter to Ext.rpc to control csrf_exempt decoration.
True (default) to ignore CSRF_TOKEN, False to keep it. (deal with it!)