geo_in_rectangle: support east longitude to west longitude in south area with index

TODO: Document it.

geo_in_rectangle(column, "-100x-100", "-200x100") means

       -100  |   100
     ---+----+----+---
             |
        +- -100 --+
        |    |    |
        +- -200 --+
             |

geo_in_rectangle(column, "-100x100", "-200x-100") means

       -100  |   100
     ---+----+----+---
             |
     ---+  -100   +---
        |    |    |
     ---+  -200   +---
             |