PyAbel/PyAbel: v0.9.0rc1

This is a release candidate for v0.9.0.

Corrections and improvements to the lin-BASEX method implementation, as well as improvements and extensions of the analytical Abel-transform tools.

Here is a full list of changes in v0.9.0rc1:

• Correct behavior of relative basis_dir in basex under Python 2 (PR #336).
• Improvements in tools.analytical.SampleImage class: more consistent and intuitive interface, accurate Abel transform for existing images, additional sample images with exact Abel transform (PR #339, #352).
• Analytical Abel transform of axially symmetric piecewise polynomials in spherical coordinates (PR #339).
• Offline HTML and PDF documentation is now available at Read the Docs and can be built locally (PR #343, #348, #349).
• Important changes in the lin-BASEX implementation (PR #357):
  • It was erroneously producing even-sized images with offset origin. Now the output is odd-sized and properly centered.
  • Output images for radial_step > 1 were scaled down by the same factor. Now they have the save size as the input.
  • The sign of Beta for odd Legendre orders is reversed to be consistent with PyAbel conventions (zero angle is upwards, towards smaller row indices).
• Transform() with method='linbasex' now always stores the radial, Beta and projection attributes, so there is no need to pass return_Beta=True in transform_options (PR #357).