Clean up code; added comments and used variables for each boundaries
Changed solvers and using Distribute_problem properly.

lagrange_step/step_po.cc
Making use of the NSPP::Distribute_problem parameter.

Always using OOMPH-LIB's GMRES now.

agrange_square/sq_lgr.cc
Always using OOMPH-LIB's GMRES now.

Trilinos fails for high Noel, hence using oomphlib's one.
new file:   gen_test_list.sh
new file:   lagrange_step/gen_test_list.sh