add. test for backend connections
fix. ref to self.active rather than self.registered
fix. "all_urls" view.  Build list under the assumption that hashes are used to key each response with key signatures.
mod. add exception handling if reading key sigs breaks.
mod. rather than ignore all cache entries when a non-hashed key is seen ignore only those keys.
mod. ensure user input is unicode and escaped.  Handle exceptions on hash generation and verification.
fix. handle exceptional cases where in queue raises IOErrors in requests_notifications_callback
fix/mod. remove "data_type" kwarg and default all aggregate types to Python standard FloatType (don't use numpy types).
fix/mod. remove "data_type" kwarg and default all aggregate types to Python standard FloatType (don't use numpy types).
mod. docs to refer to corect package name.
rm. experiments section from docs.
add. Ipython notebook and pickle backups
add. more robust reporting when requests fail.
mod. structure the .gitignore a bit more clearly.
Merge pull request #16 from rfaulkner/master

"all requests" view, bad numeric types in requests, exception handling in callbacks