Generate custom modal content on page load

I had the thought of bringing in a tempting library but it seems overkill. Generating the modal's HTML goes a little something like:
 - The page loads with little interactive modal html
 - We iterate through the event sources and pull out each of the names
 - For each of the names we give it some metadata (camelCase of the name) to use later on when I make the customise checks actually change the main content
 - There's a 'template' in the modal which is just a div with some handlebar-esque tags inside it which get replaced with the event name data. Also update the total # checked.
 - We delete the template
 - These sources are added to the DOM and event listeners are added to them in the same manner that they were previously

Also updated a check that was out of place.