[geo] provide more flexible Spatial controls (#4032)

Before this PR the only way to query lat/long is in the shape of 2
columns that contains lat and long.

Now we're adding 2 more options:
* a single column that has lat and long with a delimiter in between
* support for geohashes - geohashes are cool

setup.py

@@ -58,6 +58,7 @@ setup(
         'flask-wtf==0.14.2',
         'flower==0.9.1',
         'future>=0.16.0, <0.17',
+        'python-geohash==0.8.5',
         'humanize==0.5.1',
         'gunicorn==19.7.1',
         'idna==2.5',