Merge very close points  (1~2 meters)

Number of unwanted way have dropped significantly :-)
From 1606 ways -> 511 ways
Remove database dependency and add support for merged shapefile

Automagicly detect shapefile, 2 type of shapefile supported :
- district only (Uganda_districts2010.shp)
- merged district+region (districtReSimRenamed.shp)

Drop database code, save to an .osm file instead.

Build upper admin area (subregion) from district (works again with the help
of the previous commit :-)