Remove jQuery

[ivanvanderbyl]

More to reduce vendor bundle size: We can remove jQuery and use native events. We're only targeting evergreen browsers anyway.

• [x] Replace Ajax with https://github.com/stefanpenner/ember-fetch
• [x] Use native event dispatcher https://github.com/rwjblue/ember-native-dom-event-dispatcher/
• [x] Remove jQuery from build

Expected improvement: ~12%