instantiate default renderers in map, fix #2523
Doubleclick and scrollwheel zoom already can be forced to remained centered on map center. Now the same for touchzoom
Doubleclick and scrollwheel zoom already can be forced to remained centered on map center. Now the same for touchzoom
Update changelog related to touchZoom:center

Adding change of accepted pull request https://github.com/Leaflet/Leaflet/pull/2527 to changelog.
update npm deps
fix freeze on multiple setViews, close #2521, close #2236, close #2485
add karma launchers to deps to fix build
Control Layers constantly trigger mouseover and mouseout

fix to expand and collapse constantly firing: mouseenter and mouseleave
commit pull from upstream master