Ensure that local exports have preference over export *

Whenever an `export *` statement is used, the variable `$__exportNames` is declared as the array of known export names. Before updating a binding for an `export *` item, we first check against this list and skip if already present.

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1439

Closes #1439.
Fix typo in test
Rename `String#contains` to `String#includes` as per recent TC39 meeting
Parser.parseTypeReference_() takes no parameter
Format ModuleEvaluationError stacks as source.

Module evalution errors have stacks with line number in to functions bodies not files.
Print the source and indicate the errors by markers in the output.

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1520

Closes #1520.
Gulp WIP and mocha adapter
clean up
gulp unit tests