0.2.0

A major release with significant new functionality and some small backwards-incompatible changes.

New features:

• PR #124, census: New census notebook example, showing how to work with categorical data.
• PR #79, tseries, trajectory: Added line glyph and .any() reduction, used in new time series and trajectory notebook examples.
• PR #76, #77, #131, etc.: Updated all of the other notebooks in examples/, including nyc_taxi.
• PR #100, #125: Improved dashboard example: added categorical data support, census and osm datasets, legend and hover support, better performance, out of core option, and more
• PR #109, #111: Add full colormap support via a new cmap argument to interpolate and colorize; supports color ranges as lists, plus Bokeh palettes and matplotlib colormaps
• PR #98: Added set_background to make it easier to work with images having a different background color than the default white notebooks
• PR #119, #121: Added eq_hist option for how in interpolate, performing histogram equalization on the data to reveal structure at every intensity level
• PR #80, #83, #128: Greatly improved InteractiveImage performance and responsiveness
• PR #74, #123: Added operators for spreading pixels (to make individual datapoints visible, as circles, squares, or arbitrary mask shapes) and compositing (for simple and flexible composition of images)

Backwards compatibility:

• The low and high color options to interpolate and colorize are now deprecated and will be removed in the next release; use cmap=[low,high] instead.
• The transfer function merge has been removed to avoid confusion. stack and others can be used instead, depending on the use case.
• The default how for interpolate and colorize is now eq_hist, to reveal the structure automatically regardless of distribution.
• Pipeline now has a default dynspread step, to make isolated points visible when zooming in, and the default sizes have changed.