Changed highest_resolution_for_data

highest_resolution_for_data will now work even if
the centroid of the area_to_get is not inside a
boundary that contains field_to_get.  It will
only return None if there are no boundaries that
contain field_to_get in boundary_list.
Merge branch 'master' of github.com:harbieism/HealthAround.me into get_field_for_area_tests
Added some trash files to .gitignore.
Merge branch 'master' of github.com:harbieism/HealthAround.me into get_field_for_area_tests