Special program tailored for Uganda admin OSM import

Ignore shapes thar are causing issues (infinite loop)
Workaround for defective shape + add dump to osm file

Use only outer ring for polygon, inner ring aren't real.
Use only first polygon for multipolygon, the others are garbage.
Add sql_osm.py to dump database to an osm file.

Still some issues :
- result have some duplicate segment (which should'nt happen)
- simplification and way are not optimal due to those duplicates
- still 1 shape causing an infinite loop