Remove trailing whitespace.
Port overplot web UI to Google Maps API v3.

Besides G* -> google.maps.* namespace changes, the main change was around
custom overlays and their life cycle. On the plus side, getting click events to
work right is much simpler now (both because there's more panes we can add DOM
nodes to and because info windows don't have enormous shadows anymore).
Switch to async Google Analytics snippet.
Update TODO.