Closes #123. Add Mustache support.

examples/simple-jsbeautifyrc/test.mustache

@@ -0,0 +1,16 @@
+<h1>{{header}}</h1>
+{{#bug}}
+{{/bug}}
+
+{{#items}}
+{{#first}}
+<li><strong>{{name}}</strong></li>
+{{/first}}
+{{#link}}
+<li><a href="{{url}}">{{name}}</a></li>
+{{/link}}
+{{/items}}
+
+{{#empty}}
+<p>The list is empty.</p>
+{{/empty}}

lib/language-options.coffee

@@ -159,7 +159,7 @@ module.exports =
       when "CoffeeScript"
         beautifyCoffeeScript ?= require("./langs/coffeescript-beautify")
         beautifyCoffeeScript text, self.getOptions("js", allOptions), beautifyCompleted
-      when "Handlebars"
+      when "Handlebars", "HTML (Mustache)"
         # jshint ignore: start
         allOptions.push indent_handlebars: true # Force jsbeautify to indent_handlebars
         # jshint ignore: end