An oomph-lib interface to access pde2path problem structs

The source code published here, provides an interface to plug output of the Matlab bifurcation package pde2path into the finite-element library of multi-physics problems oomph-lib.
It makes use of the MATLAB Engine API for C++, which became available with version R2018b. Oomph-lib output data is written to plain text files, which can be read easily by Matlab used as starting points for continuations in pde2path in a straightforward manner. As the pde2path output is a Matlab struct, the data is not easily accessible from within oomph-lib. The present framework makes it possible to access meta data and parameters from the problem struct created by pde2path automatically and use it as input for calculations with oomph-lib.