hippylib/hippylib: Version 2.0.0

This major release of hIPPYlib includes the following new features:

• Non-Gaussian Bayesian inference capabilities using advanced dimension independet Mark Chain Monte Carlo methods (mMALA, pCN, gpCN, ISMAP).
• Support domain-decomposition parallelization: new parallel random number generator, and refactored randomized eigensolvers
• Basic documentation of all classes in hIPPYlib using sphinx (thanks to E. Khattatov and I. Ambartsumyan)

Interface changes:

• The parameter, usually labeled a, throughout the library, has been renamed to m, for model parameter.