Load some slides and navigate through them + tests
Add a default cache for slide GET requests
Add some CSS styling for presenting on a big screen
Store slides in MongoDB and update API to fetch from DB
Add example directive that uses arrow keys to change slides
Add client-side routing, with home and edit slide routes

This commit also introduces event broadcasting as the arrow key directive needs to be tied to the body but communicate with the slideshow controller which is now loaded by the router.
Implement edit feature, set URLs when changing routes
Remove event.preventDefault() from key press directive

This was added in error and does nasty things such as prevent moving the cursor along input fields.