[mkgmap-dev] Commit r4845: merge from faster-mp branch

Version mkgmap-r4845 was committed by gerd on Wed, 05 Jan 2022 merge from faster-mp branch - don't render natural=coastline in lines - implement faster (but possibly less reliable) algorithm to render complex multipolygons - don't render MP without tags (old code did that when all tags were removed because they did not appear in style rules, see field tagsIncomplete) http://www.mkgmap.org.uk/websvn/revision.php?repname=mkgmap&rev=4845