first successful spike of registering owin middleware
got the new OWIN middleware bits refactored and cleaner.
added many more file types to MimeType.  Closes GH-583
added etag, length, and last modified support to IFubuFile
added some new extensions on ICurrentHttpRequest for reading headers
added new builder chained methods to OwinCurrentHttpRequest and more ext method helpers
added the new base class for FubuMVC centric OWIN middleware.  Closes GH-585
created a new Middleware namespace in OwinHost
checkpoint: spiked out the static middleware
checkpoint:  moved middleware related unit tests to their own namespace
first couple use cases for the static middleware
added the static file access rules
added the initial rights assertion check into the static middleware
got the logic for the if-match header and static files
added the if-none-match header logic to the static file middleware
added the if-modified-since header logic to the static middleware
added the un-modifed-since header logic to the static middleware
wrote WriteFileHeadContinuation
implemented WriteStatusCodeContinuation
implemented WriteFileContinuation