v0.13.0

Bugfixes

Fixed easeTo pan, zoom, and rotate when initial rotation != 0 (#1950)
Fixed rendering of tiles with an extent != 4096 (#1952)
Fixed missing icon collision boxes (#1978)
Fixed null Tile#buffers errors (#1987)

New Features & Improvements

Added symbol-avoid-edges style property (#1951)
Improved symbol-max-angle check algorithm (#1959)
Added marker clustering! (#1931)
Added zoomstart, zoom, and zoomend events (#1958)
Disabled drag on mousedown when using boxzoom (#1907)