+ decrease way references in osm_node_chain_free
+ remove dirty flag in successful upload
+ create visual representation for node that get tags and remove
  it from nodes that have all tags removed
- Tag database, e.g. from
  http://wiki.openstreetmap.org/index.php/Tagwatch/Descriptions/de
+ clean up mouse handling
+ cleaner selection handling with respect to invisible nodes
+ switch to goocanvas
+ use normal mercartor instead of utm
- check bounds for placed/moved nodes
- scale (overlay?)
- include ways, a node is part of, into relation check
- remove double points from polygons
- avoid duplicate nodes in ways after node removal
- prevent placing of things outside map
