= http: small optimization in ParserInput
! http: fix raw queries still performing %-decoding and not being rendered as raw, fixes #330

Up to now queries parsed in Uri.ParsingMode.RelaxedWithRawQuery did not have a
dedicated model class. Rather they were parsed into the `key` member of
Uri.Query.Cons instances. This patch changes this, raw queries are now parsed
into the `value` member of Uri.Query.Raw instances. Additionally the Query
type now has an additional `isRaw: Boolean` member.
Merge pull request #331 from sirthias/wip/330

#330: http: fix raw queries still performing %-decoding and not being rendered as raw
Added support to play-json with basic error handling.