Some updates for the library

Thanks for providing this library. Overall it's working really great.  We've made a couple of changes that we think you should incorporate.

1. Support for environments using mb_string overloading
** This should be obvious. It's slightly intrusive, but critical for environments with a different default encoding.

2. Support for deserializing an AMQPConnection
** This came up for us when experimenting with RPC.  We experimented with shipping exceptions that the RPC Server was sending to the client.  Unfortunately the exception had an AMQPConnection object in it's stack trace that failed when \_\_destruct was called.  Adding a \_\_wakeup handler seemed to be the easiest way to resolve this.

3. Surpress fsockopen warnings
** An exception is thrown immediately afterwards.  No sense in emitting essentially useless warnings.

Thanks again!