(PR #1235) Add option to rewrite path in set-cookie headers

[swillis12]

Requesting ability to rewrite the path of a cookie in the set-cookie header. I submitted PR #1235 building on top of what was there for #1009. I added some documentation and test cases and am open to feedback. I look forward to having this merged in.

Example usage:
"cookiePathRewrite": "/"

This will rewrite cookie paths from /dummyPath to /. This is useful when using Tomcat and each application is hosted in it's own "context" (which is the war file name), so the path for each cookie is set to the war file name.

[swillis12]

Travis CI failing for #1235 due to #1167

[Aijunwei]

Would love to see this merge