fix length calc for 2-element vectors (fixes bug that was preventing max length logic for line join miters)
beginnings of overzoom support (but still need to re-calc styles/geometries for overzoomed tiles)
initial (hacky) support for Mapbox vector tiles
proof of concept, needs to be extracted to properly support multiple formats/sources
merge overzoom
switch to mapzen fork of vector-tile-js (has geojson methods)
start extracting format/source-specific loading to new TileSource object
continue extracting and generalizing tile sources/formats
allow easier switching between mapzen geojson and mapbox mvt
tile source presets can be set in URL
update readme with tile format and example URLs
workers: move network, projection, and geometry construction to web workers
fix bug with tiles not being unloaded on zoom
syntax
workers: cancel pending tiles on the web worker side
stop tracking tile within worker after load
track tile visiblity & map view bounds, and only render tiles within bounds
save tiles up to 2 zoom levels away (instead of 1), and make configurable
remove dupe bounds update
set tile scale in web worker to fix tile edge detection
add an outline around lakes/ponds to demonstrate poly-outlines on polygons
only re-render the map when dirty flag is set