Add support for type annotations in let
Merge branch 'master' into let-type-annotations
Merge pull request #166 from laszlopandy/master

Allow elm-server to use a different port than 8000.
Start generating elmi and elmo files to permit sharing of types, values, and infix info between modules.
Merge pull request #165 from A1kmm/let-type-annotations

Support type annotations in let
Minor code changes to help allow custom infix precedence and associativity.
Start using the given output-directory
Merge branch 'master' of https://github.com/evancz/Elm
Fix issue causing build error.
Fix bug in setting headers.
Fix broken build.