fixed ambiguous constructors, added a note for Mac OS X devs, bumped copyright, updated deps
bumped RSS dep to match new version bas released
fixed documentation, faulty arity
Fixed typo in Server.Framework.Logging.
copyright fix
Merge pull request #220 from bitemyapp/master

fixed ambiguous constructors, added a note for building on OS X, updated copy right, and bumped dependencies to more recent versions.
Merge pull request #237 from gintas/typo

Fixed typo in Server.Framework.Logging.
Added support for etags when downloading the package index.

Now the server will return a 304 status code instead of a 200 (with a full
response) if a client includes an up-to-date etag in the request.

HttpUtils in cabal-install already has support for etags, so this should
immediately make consecutive "cabal update" calls significantly faster once
deployed.

ETags should also be properly supported for PackageTarball and DocTarball.

This change adds a generic helper in Distribution.Server.Util.Happstack (useETag)
that both sets the ETag header in the response and checks the response
for a matching ETag, short-circuiting with a 304 on match.