Initial stuff for showing aggregated maps.

Currently just shows the correct starting map for each category, but there's
no location pins, no AJAX fetching of Topic data, etc.
Expand category map to fill more of window
Change class to id
Properly get the category form on Category Map working nicely
Improve form layout of category map
Make site header smaller.
Add pins etc to category map
Remove JS logging
Add Pepys' homes to the category map
Add hover labels to markers on category map:
Turn off default Leaflet tooltips
Add sidebar link to category maps
Bump CSS/JS version numbers