Added a type class that the implementation should provide (this fixes
the issues that I had to get the full server to compile :))
Updating the server implementation to use/abide to the API
copied the joinPath method over from the Yesod typeclass into its own
typeclass. We need this in the client to create the urls
Update the yesod instance to use the joinPath implementation from HSyncServer
Removed the if_ import stuff for monoid
Updated dependencies in the cabal file. We now depend on the
hsync-server-api. Also, some associated changes in Client + switched to
generalized newtype deriving instead of the manual instances for Monad,
Functor, etc
Remaining client changes to cope with 1) new dependencies, and 2) some
wrappers around the types in Hsync.Common.Types,.