Socket mutexes are no longer really required, and so have been removed.
Added more tests for network encoding functions, and the URL parser.
The URL parser now returns a path preceeded with a '/' instead of cutting it out. Added get_uri() to URL, for getting the whole URI, so users don't have to concat it themselves from the more specialised functions.
Fixed default socket connect timeout checking for the wrong value.
Fixed request_type_strings not containing all of the possible request types.
Fixed README using old socket close syntax.
Cleaned up the examples a bit.
