Update dependencies: clojurescript, om, compojure
Refresh Om when Figwheel updates

When changing components defined in a separate file, then the code
changes will reload, but Om will not immediately notice. To prevent this
we explicitly signal for Om to refresh when Figwheel reloads.

Idea and code taken from http://blog.michielborkent.nl/blog/2014/09/25/figwheel-keep-Om-turning/