Revert "Disable ScrambleSuit Session Ticket handshake (Fixes #21)"

This reverts commit cc9e85af8e31582f44704c1d7b603611b662b6af.

obfsproxy-0.2.7 contains the fix for what was causing Session Ticket handshake
failures, and a call has been sent to relay operators to update obfsproxy.
Failures will still happen with bridges running obfsproxy-0.2.6, but by the
time ScrambleSuit is widely deployed (and in use), people should have updated.

Fixes #26