Release 4.6.0

Change summary since 4.5.0

New features/Improvements

• Fixes and improvements to contour plots: now can use non-uniformly sampled
  grids and have masked regions (PR#326).
• Added MinorPlotAxis (PR#288).
• Improved gather points for line plots (PR#318).
• Added line plot downsampling via Largest Triangle Three Buckets
  algorithm (PR#317).
• Added Dash/Zeal docset generation (PR#194).
• Python 3 support (PR#301).
• Use set_bounds for Zoom to reduce number of events fired (PR#233).
• Added more color maps and a DiscreteColorMap class (PR#275).
• A new base "1D plot" class introduced for handling one-dimensional plots,
  including refactoring the existing Jitterplot and adding 1D scatterplot
  variants that render markers, lines or text (PR#209).
• Replaced chaco.base.bin_search by numpy.searchsorted-based routine for
  5x speedup and remove use of zip in chaco.base.arg_find_runs in favour of
  column_stack for 10x speedup in bad cases (PR#263).
• ImagePlot refactored to clarify transformation applied to images and allow
  easier reuse of transformations in subclasses (PR#147).

Fixes

• Fixed issues with contour plots on Python 3.5 (PR#329 and PR#332).
• Fixed issue with diff of boolean arrays on newer NumPy versions (PR#329).
• Fixed occasional IOError crashes in spectrum demo (PR#323).
• Fixed issue with range zoom selection being non-transparent (PR#309).
• Fixed lasso selection for newer NumPy (PR#307).
• Fixed timescale tests and calendar timescales (PR#298).
• Fixed selection alpha for line scatterplot (PR#287).
• Fixed undefined variable error in DataLabel (PR#282).
• Fixed sign inversion bug in Base1DMapper (PR#222).
• Fixed default position attribute in BetterZoom tool (PR#241).
• Workaround RuntimeWarnings from nanmin and nanmax in ImageData.get_bounds
  (PR #242).

Maintenance

• Updated install instructions and quick start guide (PR#292).
• Removed special casing of powers of 2 in tick generation (PR#314).
• Added code coverage notification via codecov (PR#297).
• Fixed broken documentation URLs (PR#270).
• Use containers for Travis CI (PR#276).
• Automatic PEP386-compliant version numbering (PR#269).
• More comprehensive testing for AbstractDataSource subclasses. That
  includes ArrayDataSource, FunctionDataSource, GridDataSource, ImageData,
  MultiArrayDataSource (PR#244).