feature(server): Add input validation to POST `/unload`
fix(server): Remove the inline `style` tag which is blocked by CSP.
fix(client): Change the left margin of the hits graph to 30px to accommodate up to 6 digits in the y-axis
fix(client): Make the referrers and top pages line up.
chore(client): Create a shorter form factor for the hits graph.
refactor(client): Use a colored fill on the hit graph
feature(client): Add a start/end date picker on the daily hits screen.
feature(server): Add a `dateFormat` template filter.
fix(client): Change the type of the `date` input elements to `datepicker` to avoid confusion in Chrome.
fix(client): Use the correct hostname when loading the daily hits
fix(client): Fix the hits graph fill on page resize.
chore(style): Lots of style updates, esp for mobile.

* Nicer responsive layout.
* Remove the "exit to" screen on GET-site-hostname-path until the inconsistencies are tracked down.
* Make GET-site-hostname-path look similar to GET-site-hostname
* Add the date picker to GET-site-hostname-path
chore(style): Show the referrers in two columns between 500 and 700px.
Merge branch 'hits-graph-updates'