Minor cleanup of http.parse_init* methods.
Handle non-integer port error in parse_init_connect correctly
Unit test for ODict.__iter__
Basic certificate store implementation and cert utils API cleanup.
Generate certificates with a commencement date an hour in the past.

This helps smooth over small discrepancies in client and server times, where
it's possible for a certificate to seem to be "in the future" to the client.
Sanity-check certstore common names.