Merge pull request #1 from panagosg7/srcspan

Changes to accommodate nano-js
Renaming Cast to DownCast and adding explicit UpCast expression
Merge pull request #2 from panagosg7/add_upcast

Adding Upcasts in the language
PP for triple.
Renaming Cast to DownCast and adding explicit UpCast expression
Started parser changes
Adding support for type annotations inside comments.

  - Porting Token.hs from parsec to fiddle with `multiLineComment`, so that
    comments starting with "/*:" (or sth equivalent) are not consumed as
    comments.

  - For the moment type annotations are just tugged in the VarDeclStmt, but this
    is easily extensible.
Restored types in parser.
Fixing the API.

  - In addition to parseJavascriptFromFile there is parseJavascriptFromFile'
    that accepts a parser to parse annotations at certains parts of the code.

  - At the moment there is just a hole at parseVarDecl. But it should be
    straightforward to add this at many places.
Fixes in annotation parser.
Merge pull request #3 from panagosg7/pp_triple

PP for triple.
Merge pull request #4 from panagosg7/parser

Adding support for annotations to the parser
single cast operation
removing Cast
added Cast back in...
Merge pull request #5 from UCSD-PL/intersections

Intersections