Enabling TLS1.2 support

Unfortunately OS X comes with 0.9.8 bundled. There is a way to
install a recent version through homebrew, however it is
extremely hard to make it link agains brewed version without
tricking link version
TLS 1_1, 1_2, Ssl 2 is enabled by features
Merge pull request #46 from vhbit/tls1-2-support

Enabling TLS1.2 support
WIP: certificate/pkey generation & PEM export