Make page scripting work with Ajax navigation.

One way to make scripts run when loaded via jQuery Mobile's Ajax
navigation is to place them at the end of the [data-role="page"]
element. This commit does that.

<head> is not evaluated with Ajax navigation, so this commit also
includes Leaflet CSS and JS in <head> of every page. They'll then be
available any time the user navigates to map.

Also, Leaflet's sizing is still a little tricky. Seasoned to taste.

Documentation:
http://demos.jquerymobile.com/1.0/docs/pages/page-navmodel.html

Fixes #8.