geo_in_rectangle: support east longitude to west longitude without index

TODO: Document it.

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

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

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

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