Route patterns that were empty strings were being permissive. Handle the falsy case.

Also added some filtering tests.
Added more filtering tests
Added release notes section to readme
Added keywords to package.json
Updated readme
Added ability to tee a request or response stream to any writable stream. Added test case.
Incremented micro version
Merge branch 'tee'
Merge branch 'master' into gh-pages
Added tee() documentation.