Bootlint integration

app/views/layouts/_bootlint.haml

+:javascript
+  jQuery(document).ready(function() {
+    javascript:(function(){var s=document.createElement("script");s.onload=function(){bootlint.showLintReportForCurrentDocument([], {hasProblems: false, problemFree: false});};s.src="https://maxcdn.bootstrapcdn.com/bootlint/latest/bootlint.min.js";document.body.appendChild(s)})();
+  });

app/views/layouts/_head.html.haml

@@ -16,6 +16,7 @@
 
   = render 'layouts/google_analytics' if extra_config.has_key?('google_analytics_id')
   = render 'layouts/piwik' if extra_config.has_key?('piwik_url') && extra_config.has_key?('piwik_site_id')
+  = render 'layouts/bootlint' if Rails.env == 'development'
 
   -# Atom feed
   - if current_user