Add Purkinje support to batch simulations and minor fixes

[bergolho]

Hi Sachetto,

In this pull request, there is now support to execute Purkinje simulations using the 'MonoAlg3D_batch' binary with MPI. Also, there are few additions to the solver, like a new script to concatenate a ALG and FIBERS files into a single one, a new function to print UUID of the GPU device and I included a new field to the output 'pmj_delay.csv' that tells when a propagation block occurs in a terminal during a Purkinje coupled simulation.

Regarding fixes, I found a minor error when saving the output file using the 'MonoAlg3D_converter'. Looks like the filename string was missing the end of character '\0', so the file could not be read directly from Paraview without renaming it.

Also, I am working on a new 'save_mesh' function that can calculate and plot the LAT together with multiple AP traces from different cells in the grid. Finally, I am trying to improve the performance of the 'activation_time' calculus, which is serial right now. It will be good if we could use a #pragma statement, but we need to avoid race conditions when writing to the 'persistent_data' struct. All these working in progress are written in the 'ToDo'.

Best regards,
Lucas