When enabled, inter-packet delay will be randomized between 0 and 10
ms in 100 usec intervals.  As experiences from ScrambleSuit (and back
of the envelope math based on how networks work) show, this is
extremely expensive and artificially limits the throughput of the link.

When enabled, bulk transfer throughput will be limited to an average of
278 KiB/s.

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.