Don't double-close cURL sockets

Fixes the fatal error in HHVM (null pointer reference)
Use $transport::test() for checking SSL in tests

See #101. Turns out fsockopen was overriding this, but we have contextual
checking support now, so let's use that.
Disable SSL support on HHVM

See https://github.com/facebook/hhvm/issues/2156
Merge pull request #106 from rmccue/hhvm-fixes

Fix support for HHVM