This reverts commit 8d61c6bc.

On second thought, don't do this.  API not final, and some of the stuff
might not be a good idea after all.

As of `15b960d55905877a840fe605a41a8139bffb5329` goptlib supports
IsClient, IsServer, and handling the StateLocation.

Yes this means you need to use goptlib out of git.

This fixes #6.

Part of #6, still need to make logs nicer.

This fixes #3, and brings the code to be on par with the delopyed
versions of ScrambleSuit in terms of features.

This also adds the drgb-seed option to the `-gen` obfs4proxy output.

This should fix sockets getting stuck in CLOSE_WAIT.

On second thought instead of using log.Panicf(), panic() and do the
logging with recover().  This somewhat centralizes logging in
obfs4proxy, which will be easier to change when I invariably decide to
do logging differently in the future.

This fixes #1.

 * The old and the busted: obfs4-[client,server].
 * The new hotness: obfs4client.
 * Add obfs4.ServerHandshake() that servers need to call after a
   successful return from Accept().  This allows implementations to
   move the handshake into a goroutine or whatever.