[Fix bug 873789] Make it easier to add event coordinates.

* Add mapbox.js to static
* Fix client side messaging UI
* Make showMessage generic
* Add search bar to map modals
* Initialize map modal with user lat/lon
* Prepopulate event form using userprofile data
* Try to autopopulate with reverse geocoding
* On map zoom after search populate lat/lon
* Add geolocation button to map modal