Add support for request & response headers

Supports matching headers on an incoming request and including headers
in the client driver response.
Merge pull request #11 from joelittlejohn/headers

Add support for request & response headers
Update version pending release
Update version for next release cycle
Update latest version in readme
Correct project name in the README.md
Merge pull request #12 from joelittlejohn/patch-2

Correct project name in the README.md
fixed issue with sweetening override status code
Merge pull request #14 from jaroslawZawila/master

Allow explicit override of response status when sweetening responses
Remove println from pull request
Clarify test description
Update version for release
Update version for next release