Added Basic Auth for outgoing route/channel calls

If username and password are set as options on the channel then an
authorization header is added to the request.
If username and password are absent no authorization headers are sent.
Fixed some typos and language. Added dependencies badge.
Merge branch 'master' of https://github.com/jembi/openhim-core-js

Conflicts:
	README.md
Fixed some typos and improved readability.
Merge pull request #19 from psbrandt/master

Slight improvements to the README.
Added dev dependencies badge to readme
Merge pull request #21 from jembi/route-basic-auth

Added Basic Auth for outgoing route/channel calls
Merge branch 'master' into messagestore

Conflicts:
	package.json