Build mkgmap/mkgmap #1293

Improve house number processing: - don't add a further label for an unamned road if there are no house numbers (reduces IMG size) - if an unnamed road is used for addr:place addresses, forget a previously assigned label from a nearby named road. This happened quite often where unnamed e.g. a highway=unclassifed is connected to a named road and mkgmap identified the unnamed road as a possible service road (method identifyServiceRoads()) (reduces IMG size and prevents false matches where the same address is found searching for place ABC or road XYZ)