update `/map` to use new style / base map
add comments about the two time values for measures
(database insert time vs. observation time)
change the missing value for the `psc` field to -1

the former 0 is an actual legal real value
enable retina images on new `/map`
tweak the initial map position to have equal `empty` space on top and bottom
let the navigation links point to the new map
add `leaflet-hash` plugin, to allow map positioning by url hash
update to gunicorn 18.0 which we use in the upcoming prod environment
adjust log file names to match upcoming prod environment
correct importer code and make sure to update mapstat table
only update mapstat in importer code if there are entries left
drop default importer batch size to 1000
allow nicknames with just two letters, you are welcome jr :)
remove old markercluster map_world, refs #33
forgot to remove the `location_10km` mapstat key