Update highlight.js to 8.1

Also added support for less common languages. All languages from
http://highlightjs.org/download/ now supported

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/assets/javascripts/application.js.coffee

@@ -23,7 +23,7 @@
 #= require g.raphael-min
 #= require g.bar-min
 #= require branch-graph
-#= require highlightjs.min
+#= require highlight.pack
 #= require ace/ace
 #= require d3
 #= require underscore