[Bug] Region bbox coordinates inconsistent, need attention

[mradamcox]

Describe the problem
The Region objects for individual cities work fine, but the Louisiana and Global regions don't. The confusing thing is, that in the db, the x0, x1, y0, y1 coordinates seem backward for the city-level regions, and correct for the other two. This warrants investigation...

Expected behavior
A document with no city-level region attached to it should default to the larger Louisiana region extent when loading the georeferencing interface. Currently, the map doesn't initialize properly, due to this coordinate issue.

Additional context
Very likely related to #6, in some way.

[mradamcox]

Compare the bbox coords of the first two entries here: https://github.com/mradamcox/loc-insurancemaps/blob/4d3c572b97a16961a3bcb7366413fa39adb0cec4/loc_insurancemaps/fixtures/la-regions.json

Louisiana, looks good in the fixture but doesn't seem to work properly.
Gretna, coordinates are swapped in the fixture but it does seem to work within the app.