Mpl-stereo

Added
* Wiggle stereograms
Changed
* Better docs

Added
* More test coverage
Changed
* Fixed `axstereo.autoscale_z()` not doing anything if `zlim` was set

Added
* Church full color anaglyph example
* Support for full color image anaglyphs, with methods `'dubois'`, `'photoshop'`, `'photoshop2'`
* Support for colormaps in image anaglyphs
Changed
* Default `zscale` is now 1/4 x-axis range, not 1
* Fix anaglyph color ordering

Added
* Consistent `zlim` handling added, with functions `get_zlim`, `set_zlim`, `autoscale_z`, `_calc_bounding_zlim`
* Method `redraw` for side-by-side axes
Changed
* Default `zscale` fixed
* `z_scale` and `z_zero` renamed to `zscale` and `zzero`
* `AxesStereo` class renamed to `AxesStereoSideBySide`
* `AxesStereo2DBase` abstract base class added

Changed
* Fix anaglyph color ordering

Added
* `AxesAnaglyph.imshow_stereo()` for generating anaglyphs from existing image data
* `mpl_stereo.example_data` module
* `AxesStereo2D` and `AxesStereo3D` keep track of their artists in `.artists_left` and `artists_right`
* Derivation of geometry
Changed
* Minimal whitespace between AxesStereo2D subplots