Framework for performance-portable parallel computations on unstructured meshes

Version of Firedrake used in 'The geometry of optimally transported meshes on the sphere'.

This release is specifically created to document the version of
Firedrake used in a particular set of experiments. Please do not cite
this as a general source for Firedrake or any of its
dependencies. Instead, refer to
http://www.firedrakeproject.org/publications.html