[ENH] fixed compilation, utilization of Salomon modules, inclusion of PETSc framework in the parallel version of levenberg-marquardt algorithm, minor fixes of the acsf example and run scripts

[NEW] [ENH] L-M linear problem solving parallelized using PETSc. Removed unnecessary mpi.h includes.

[ENH] Added a new folder "sandbox" to prevent mixing of development testing and demonstratory examples.