map.js: fix base layer selection
map.js: fix base layer selection

snip/skylines,TobiasLohner/SkyLines,skylines-project/skylines,shadowoneau/skylines,Turbo87/skylines,RBE-Avionik/skylines,Harry-R/skylines,Harry-R/skylines,kerel-fs/skylines,TobiasLohner/SkyLines,kerel-fs/skylines,snip/skylines,skylines-project/skylines,skylines-project/skylines,kerel-fs/skylines,Turbo87/skylines,Harry-R/skylines,Turbo87/skylines,RBE-Avionik/skylines,shadowoneau/skylines,snip/skylines,RBE-Avionik/skylines,shadowoneau/skylines,RBE-Avionik/skylines,shadowoneau/skylines,TobiasLohner/SkyLines,skylines-project/skylines,Harry-R/skylines,Turbo87/skylines