UriParser now _doesn't_ decode the query string

fixes #75
The QueryParser expects a url encoded string, but the UriParser
predecodes it. This fixes the problem at the cost of needing to
manually decode the query String if all you really want is the String.
Uri Fragment is no longer decoded by the RequestUriParser

Also added a few more tests to the UriSpec
issue #75.
Merge branch 'topic/issue75'

Conflicts:
	core/src/main/scala/org/http4s/Uri.scala