Diffusion.*: Wrote class for repr rhs.
ForwardEuler.*: Changed to using arma lib.

Removed unnecessary code when using `Diffusion` class.
ForwardEuler.hpp: Small fixes. Moved save method.
main.cpp: Added test of FE.
meta.dat: Added for compiler.
Make.py: Added makefile from prj03.
Script for animating datafiles.
Small changes. Integration works.
Why listed as change?