Uc 44 Marketing email opt in

Adding marketing opt-in checkboxes to the facebook modal and the signup form.

The state of the checkbox is different depending on where the user is located. If they are in Canada, the checkbox is visible and unchecked. If they are in Europe, the checkbox is visible and checked. Anywhere else, the checkbox is hidden and checked. 
There is a function `geo.getGeoData` that returns an object like `{city: "FIXME", country: "CA", continent: "NA"}`, but these helper methods to get the country and continent are available, so I figure I might as well use them. To my eye this is abstracted as much as needed, although I could see maybe setting variables for 'eu' and 'ca'.