additional icons for apple app store, windows store
some new icons
download badges for app store, play store and windows store
search pagination
tags directive, tags on search results
show alternative platforms on detail page
Learning Layers Sign in button 'design' + extremely long text
removed home button, due to new space contraints (brand logo has same
function)
Merge pull request #148 from learning-layers/frontend_update

additional icons for apple app store, windows store