Added config parameter network.http.ssl_verify_host to support certificates.

Added config parameter network.http.ssl_verify_host to support certificates
with a mismatched or empty CN. Default is 2 (verify name match). Use 1 to simply
verify the presence of a name or 0 to allow for missing names.
Merge branch 'master' into pr/190
Cleaned up how ssl_verify_host/peer is set.