Cosmetic changes to the visualization scripts.
The map plotting commands now zoom in.

Only happens when the region is small enough. In these cases the
map projection is also changed to a Mercator projection.
Not available data correctly handled in InvDB.

The inventory database now correctly handles missing data.
Major speedup for initial import.

Is around 100 times faster then before. This makes the command line
interface feel very responsive. Also implemented a simple caching
mechanism for the config file.
Merge remote-tracking branch 'origin/master'