Fix space betweens map buttons

Fix #1460 

Test [here](http://mf-geoadmin3.dev.bgdi.ch/fix_css/prod/?lang=fr&topic=ech&bgLayer=ch.swisstopo.pixelkarte-farbe&X=190000.00&Y=660000.00&zoom=1&catalogNodes=457,477&layers_opacity=0.75&layers=ch.bafu.biogeographische_regionen)