PetIBM - toolbox and applications of the immersed-boundary method on distributed-memory architectures (v0.3.1)

This release includes suggestions from JOSS reviewers.

Added

• Add section in README and documentation on how to use the API.
• Add simple Navier-Stokes solver using the PetIBM API in the folder `examples/api_examples`.

Changed

• Rename application code `tairacolonius` into `ibpm` (Immersed Boundary Projection Method); binary program now named `petibm-ibpm`.
• Make YAML converters and operator< private.
• Move example of oscillating cylinder to folder `examples/api_examples`.
• Update optional dependency `AmgXWrapper` with latest version (1.4).

Fixed

• Remove MPI barrier in routine that creates a directory.
• Fixed memory leaks in solver programs and utility programs.

Removed