update for TLS 1.2 and new certificate handling
No need to grab the backend context anymore.

TLS backend is re-entrant now.
update for latest tls 1.2
properly bind together hostname and port.
remove unused test flag.
bump version to 0.2.0
add a documentation line
override TLSSetting's settings at the hostname/port level,
so TLSSettings can be used as a template structure, just like TLSSettingsSimple
add CHANGELOG
bump version to 0.2.1