Add Network.HTTP.Types.URI.extractPath

(as a copy of Network.Wai.Handler.Warp.RequestHeader.parsePath from
warp)
Add support for HTTPS URLs to extractPath
Add documentation and tests for extractPath
Merge test/runtests.hs into test/Network/HTTP/Types/URISpec.hs

(+ use hspec-discover)
Bump version
Add doctest driver
Re-export extractPath fro Network.HTTP.Types
Merge pull request #47 from sol/add-extract-path

Add extractPath