Also, in ParserPipeline:
* Import the LM converter and expose it through getLinearModel()
* Fix getWikiDom() to actually work (still unused)
In parse.js:
* Add --help option that prints usage information (was unreachable)
* Add --linearmodel option to output linear model JSON instead of HTML
Change-Id: Ic534e03ff40a7c9117bb63f0c635a4213d5e3406