Added pre-tags around the last code sample
Registers IDirectory and fixes instatiation of UrlGenerator.  Updates some using statements to reflect movements in Cassette.
Forgot to inlude updated packages.config
Merge pull request #14 from Cobster/update-cassette-2.1

Update cassette 2.1
Merge pull request #12 from marcusoftnet/patch-1

Added pre-tags around the last code sample
merged with latest commits from cassette.nancy master branch