context deprecation

context deprecation

1) This makes lwsws run a parent process with the original permissions.
But this process is only able to respond to SIGHUP, it doesn't do anything
else.

2) You can send this parent process a SIGHUP now to cause it to

 - close listening sockets in existing lwsws processes

 - mark those processes as to exit when the number of active connections
   on the falls to zero

 - spawn a fresh child process from scratch, using latest configuration
   file content, latest plugins, etc.  It can now reopen listening sockets
   if it chooses to, or open different listen ports or whatever.

Notes:

1) lws_context_destroy() has been split into two pieces... the reason for
the split is the first part closes the per-vhost protocols, but since
they may have created libuv objects in the per-vhost protocol storage,
these cannot be freed until after the loop has been run.

That's the purpose of the second part of the context destruction,
lws_context_destroy2().

For compatibility, if you are not using libuv, the first part calls the
second part.  However if you are using libuv, you must now call the
second part from your own main.c after the first part.