Version 0.2.2: use new API for Polynomials and HDF5

Merge pull request #15 from joefowler/github_actions

Use GitHub actions for testing

Version 0.2.1. Use ToeplitzMatrices.jl

Merge pull request #11 from joefowler/Toeplitz

Use ToeplitzMatrices package

Version 0.2.0 for Julia 0.7 and 1.0

Code finally passes Travis tests on Julia 1.0.

Version 0.1.1, for Julia 0.6

Last release for Julia version 0.6.