[mkgmap-dev] Commit r3865: code cleanup, no functional change: Create OverviewMapDataSource instance in OverviewBuilder instead of Main

Version mkgmap-r3865 was committed by gerd on Sat, 25 Mar 2017 code cleanup, no functional change: Create OverviewMapDataSource instance in OverviewBuilder instead of Main http://www.mkgmap.org.uk/websvn/revision.php?repname=mkgmap&rev=3865