Uri Fragment is no longer decoded by the RequestUriParser

Also added a few more tests to the UriSpec
issue #75.

Conflicts:
	core/src/main/scala/org/http4s/Uri.scala
	core/src/main/scala/org/http4s/parser/Rfc3986Parser.scala
	core/src/test/scala/org/http4s/UriSpec.scala
Release v0.4.1.