v0.2.1

• Use Oriented Bounding Boxes (OBB) for label collision, significantly increasing the number of labels on screen (typically about 100% increase)
• Add error/warning events that clients of the library can subscribe to (initial use case is Tangram Play, for error handling in UI)
• Add sprite_default parameter (allows for generic POI icons, etc.)
• Enforce winding order on non-tiled data sources (with option to also enforce on tiled data sources if desired, off by default)
• Fix issue preventing multiple text-based styles from rendering
• Remove "dirty" text halos (correct for premultiplied alpha)
• Reduce max global zoom to 18 by default (over-zooming will apply beyond that)
• Reduce unnecessary GL state changes for better performance
• Improve handling of standalone TopoJSON sources with a single data layer (like other data sources, no need to specify layer name anymore when only one)
• Fix issue with lighting and blend properties in mixed styles
• Re-create all textures on scene load (fixes Tangram Play bug where texture URLs change were not reflected)