[ES6] Update mozilla ast

[avdg]

(Yeah, I'm talking about fixing this mess: avdg@45fcb65)

There is a need to maintain mozilla-ast on the harmony branch if there is a need to keep it alive. As I don't have the tools (yet) to test things out in real-world usage. I don't think about maintaining this right now. However, I did take a quick look and I think one with enough time, interest and resources can do this.

[kzc]

Repeating comment here as it is relevant to this new ticket...

I believe that mozilla-ast import and export for ES5 is complete on master and is compatible with acorn --ecma5, so all new ESTree/mozilla development can take place on the harmony branch for ES6.

  --spidermonkey                Assume input files are SpiderMonkey AST format (
                                as JSON).                              [boolean]

  --dump-spidermonkey-ast       Dump SpiderMonkey AST to stdout.       [boolean]

I don't know if we should make new flags specifically for ES6 import/export?

For that matter, should lib/parser.js support an ES5 parsing mode and a separate ES6 mode as acorn does with --ecma5 and --ecma6?

[alexlamsl]

Closing as duplicate of #968