Minifier Support

[phpnode]

Adds support for minification via html-minifier.

var collection = HTMLing.dir('templates', null, null, true);
collection.render('index', {}); // output is minified

also accepts options to pass to the minifier:

var collection = HTMLing.dir('templates', null, null, {
      collapseWhitespace: true,
      collapseBooleanAttributes: true
    });
collection.render('index', {}); // output is minified

The arguments for these commands should probably be replaced with an options object, but I'll save that for another PR.