Use template literals when logging an invalid superClass
Add to and export PlaceholderParser

- Makes the error reporting of PlaceholderParser more informative.
- Adds parseModule and parseScript template tags.
- Exports parseModule, parseScript, parseExpression, and parseStatement from
  the main Traceur module, as properties of the codegeneration export.
ensure traceur System is exported not the global
Exponentiation expression should be right associative

Fixes #1245
Destructuring does not require an object any more
0.0.57
Remove runtime remove assertObject

This could not be included in the last commit due to self hostin
issues. It required a npm push before it was safe to remove.
Correct sourceMaps option in test and verify it.

Partly fixes #1254

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1258

Closes #1258, closes #1254.
Hoist function declarations in generator functions

This is so that we do not add a function where it isn't allowed
in ES5 strict mode, due to the CPS transformer.

Fixes #1172
Add support for export default FunctionExpression

and export default ClassExpression

We parse the expression as a FunctionExpression and if it has a name
we change it into a FunctionDeclaration. Same goes for ClassExpression.

Fixes #1208
Define what polyfills to include in the Makefile

The Makefile now lists the polyfills to include. These files register
themselves and then the polyfills.js initializes the polyfills for The
given global.

Fixes #1244
expose traceur.get
Add Options.diff and refactor test to use it

Set Options through setOptions to check for unknown options.
Correct sourceMap -> sourceMaps
Fixes #1254

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1259

Closes #1259, closes #1254.
Support CommonJS loading from ES6

Fixes #818
Tag git with traceur's npm version

rather than the version on bin/traceur.js
Update the version (and publish to npm)
one time without a tag to get in sync.

Fixes #1261

TBR=@arv

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1263

Closes #1263, closes #1261.
0.0.58
Ensure that generated-code-dependency tests use locals.

Some of these tests were sharing globals

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1265

Closes #1265.
Refactor uses of codeUnit from ModuleVisitor to InternalLoader

Remove unused getModuleSymbolForModuleSpecifier()
Remove ModuleDescription in favor of ExportsList and adder function

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1252

Closes #1252.
Reduce the number of functions taking options.

Pass by value in a few more places.

This version will be incompatible with es6-module-loader.

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1266

Closes #1266.
Move comprehensions to experimental

Since comprehensions have been post poned to post ES6 we should not
have them enabled by default.

Fixes #1260