Remove TBB support in Aevol

TBB is a multithreading framework that was used in making some parts of Aevol parallel. This parallel implementation is deprecated (we now use OpenMP), but some bits were left over and cluttered the codebase.

This merge request removes all code related to TBB in Aevol, except for some code in ode_solver_only_omp_knl.cpp, which will be cleaned up in a later ODE-specific merge request.