Map polyfill: Only add the iterator to values() if available.

Only add the [Symbol.iterator] to the result of new Map().entries()
if entries is available in the browser.

The problem is that IE11 and old V8 with --harmony have Map but no
iterators.

Fixes #1203
Reimplement options as es6 class CompileOptions.

CommandOptions extend CompileOptions with commander-specific
features.
Add tests for CompileOptions and CommandOptions.
Our current approach to options passes global values through module instance variables
combined with passing them as arguments. Chaos ensues. We need to pick one of these three.
Passing arguments from the API provides the most control and flexibility. We may continue
to use the global deeper in the call stack, after we are below the API calls.

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1202

Closes #1202.
Followup: Rename CompileOptions.js -> Options.js

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1206

Closes #1206.
Rename functionBody to body

Fixes #1187
instantiate postfix operator fix
0.0.53
Use string for Node version in .travis.yml

0.10 as a float == 0.1, the version should be a string.

Fixes the [Travis build](https://travis-ci.org/google/traceur-compiler).
Change the AST for ImportSpecifier and ModuleDeclaration to contain
a ImportedBinding tree.

Fixes #1154
Add support for the exponentiation operator

x ** y is now short for Math.pow(x, y)

Similar for x **= y.

https://gist.github.com/rwaldron/ebe0f4d2d267370be882
Add support for "import * as m from 'm'"

This keeps the old syntx in place. It will be removed in a seperate
PR since self hosting requires this two step process.

Partial fix for #1119
0.0.54
WIP on String.prototype[@@iterator]; Github issue #539
Use maybeAddIterator
Insert repl options at top of file based on user's choices.

Also rely less on global options.
Fixes #1213.

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1219

Closes #1219, closes #1213.
Array.from polyfill: Only use Function#call when thisArg is provided.

This was much slower than it needs to be for the common case, when `thisArg` isn't provided.
Switch to use import * as for code

This removes the support for the old syntax

Fixes #1119
0.0.55
Report options errors in REPL UI

Fixes #1229

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1230

Closes #1230, closes #1229.
Repl: Fix issue where location  was not updated.

This was a regression from 75ca1e0b25027bb152b96245a899bd7d4b57178a

Fixes #1234
Make sure async-functions work without generators.

This was due to a typo.

Fixes #1231