Consider using OCID's country bounding box data

[hannosch]

Chris from OpenCellID has improved upon our original country bounding box data set and published it at https://github.com/azurro/country-bounding-boxes. We should see how this differs from our own (https://github.com/graydon/country-bounding-boxes).

Maybe we can either merge the changes back to our own data, or switch to using the OCID data.

[hannosch]

In 229b6ec and the following commits up to 4094569 we added a much higher precision shapefile of region borders.

We now do much more precise checks of cell networks, checking their mcc to the actual region areas, as well as checking all incoming reports to see if they are inside any of the areas at all or just completely in the middle of an ocean.

[hannosch]

As a reference, the buffered map looks like this -> https://gist.github.com/hannosch/7d7c59f3bd6293bcb130 in addition to the precise map -> https://github.com/mozilla/ichnaea/blob/master/ichnaea/regions.geojson