This ensures separation of the map legend values into discrete bins and closes #56;
It also corrects a problem that certain values were being mis-classified by performing log() calls separately on all numbers in the classification step.

Signed-off-by: Matt Bernhardt <mjbernha@mit.edu>
Cleaning up call to assign quintile to map region - had set an artificial floor of 1 value, which turns out to not be necessary. This closes #58.

Signed-off-by: Matt Bernhardt <mjbernha@mit.edu>
Swapping out flexboxes for table-cell displays, thanks to better backwards-compatibility;
Adding minimal IE7 support (basically the data tab and exports only) - IE7 can't run d3.js easily, so the visualizations maybe beyond it.
Minor markup tweak to filter UI, adding a span that had been forgotten before that the new styles need.
This closes #77

Signed-off-by: Matt Bernhardt <mjbernha@mit.edu>