[mkgmap-dev] Commit r4310: Code cleanup, no change in output expected

Version mkgmap-r4310 was committed by gerd on Mon, 21 Oct 2019 Code cleanup, no change in output expected - use MultiHashMap for field deferredRelationMap in ElementSaver - use of HashMap.computeIfAbsent() in MultiHashMap might give small performance improvement http://www.mkgmap.org.uk/websvn/revision.php?repname=mkgmap&rev=4310