Close multiplexer in a strand to prevent races
Removes this_thread::yield() from ConnectionManager::Close

I was not seing any test failures without it so
there is a chance the problem this was fixing has been
solved. If not, I would like to see the original problem,
perhaps to fix it differently.
Merge pull request #49 from inetic/MAID-471-thread-sanitizer-warnings

Maid 471 thread sanitizer warnings
Merge branch 'next' of github.com:maidsafe/MaidSafe-RUDP into routing_v2

Conflicts:
	src/maidsafe/rudp/connection.cc
	src/maidsafe/rudp/connection_manager.cc
Backup: Async_result in Rudp now uses std::error_codes
Outgoing handshake packets now contain this_public_key_

In their public_key_ variable. Not the value of peer_.public_key()
as it was previously.