Merge pull request #41 from avsm/master

add with_scheme and with_userinfo functional setters
Always percent-escape semicolon in structured query encoding.

Fixes mirage/ocaml-cohttp#126. Fixes mirage/ocaml-uri#42. Creates mirage/ocaml-uri#43.
Clarify query alphabet
Merge pull request #44 from dsheets/master

Always percent-escape semicolon in structured query encoding.
release 1.6.0