arv: preview arv reports

[TollensWP]

Resolves #671.

Sorry that this diff is hard to read, this change includes a fairly substantial refactor so that the creation of the report wikitext is done on its own rather than coupled with report posting logic. Aside from the obvious, I don't think there are any changes to functionality, other than that curly braces in edit summaries will now be escaped to prevent templates from getting rendered in AN3 reports given that they don't render in edit summaries.

Because of that refactor, it's highly possible this has broken something somewhere (especially considering there's now promise chains involved, which I can only barely wrap my head around): I've done quite a lot of testing to make sure that didn't happen but would appreciate someone double-checking my work, especially with AN3 reporting.

One thing that did come up is that in AN3 reports, the logic for filling the |orig= parameter in the report template seems to be broken (both before my change and after, I think) - I would have fixed it but frankly I don't really understand what should go into that parameter in the first place. The API call is not parsed properly (the following is from the current version):

twinkle/modules/twinklearv.js

Lines 854 to 894 in 3425932

	new mw.Api().get({
	action: 'query',
	prop: 'revisions',
	format: 'json',
	rvprop: 'sha1|ids|timestamp|comment',
	rvlimit: 100, // intentionally limited
	rvstartid: minid,
	rvexcludeuser: params.uid,
	indexpageids: true,
	titles: params.page
	}).done(function(data) {
	Morebits.wiki.addCheckpoint(); // prevent notification events from causing an erronous "action completed"
	// In case an edit summary was revdel'd
	var hasHiddenComment = function(rev) {
	if (!rev.comment && typeof rev.commenthidden === 'string') {
	return '(comment hidden)';
	}
	return '"' + rev.comment + '"';
	};
	var orig;
	if (data.length) {
	var sha1 = data[0].sha1;
	for (var i = 1; i < data.length; ++i) {
	if (data[i].sha1 === sha1) {
	orig = data[i];
	break;
	}
	}
	if (!orig) {
	orig = data[0];
	}
	}
	var origtext = '';
	if (orig) {
	origtext = '{{diff2|' + orig.revid + '|' + orig.timestamp + '}} ' + hasHiddenComment(orig);
	}

Seems like the data parameter of the callback is trying to be read as an array, but the API call always returns an object. Adding data = data.query.pages[data.query.pageids[0]].revisions; at the start of that callback would convert the object to the array it thinks it is, but I don't know enough about what the |orig= parameter is even for to be able to decide whether that actually fixes the problem. I can't even really create a new ticket because I don't know what the expected behavior is, but if someone is able to explain I can probably fix it pretty easily.

[TollensWP]

Well that's nifty! Never seen that before.