the code that calls handleEntities in genPOI was building a list
of all filter funcs in the config, then used itertools.groupby to walk over
each region set, calling handleEntities and passing filters funcs for the rset.
this works fine when all of the renders point at a different world,
since rsets are sorted via __lt__ using the regiondir. when an rset appears in
the config multiple times, groupby can't sort the rsets reliably,
so a single rset is passed multiple times to handleEntities with only some
of the applicable filters. for a config with just two renders of the same world,
handleEntities would frequently be called 5-7 times instead of just 2.
this change eliminates group by, and just iterates over all the rsets, each
time plucking the list of applicable filters based on rset associated with
each filter (simple equality).
use json.dumps(sort_keys=True) to apply a consistent sorting to the output JS files.
improves the readability of diffs and making config testing easier
This fixes a bug where a world with multiple layers with different
"northdirection" values would initially load at the wrong center point
because the center for the last layer would override prior values
in the overview.collections.centers map.
Cliff Meyers