fixed; handle connection errors

includes often require making requests to other servers
which may be down. this now handles this error and properly
passes it back through to the callback instead of trying
to parse a non-existant response

closes #129
Merge pull request #192 from aheckmann/properly-handle-wsdl-connection-errors

fixed; handle connection errors
Merge branch 'master' of https://github.com/milewise/node-soap

Conflicts:
	lib/wsdl.js