cleanup the c++ portion of setup.py
remove some unused potentials
Fix deallocation bug in combined_potentials

clean up cpp stuff a bit.
delete a few unused files
remove tabs from cpp sources
fix bug in python / fortran morse potential
fix bug in systems.MorseCluster

A was set to 1., the input was ignored
add cpp version of morse potential
add option to specify the initial e, grad in lbfgs_cpp
add option to run for specified number of iterations in lbfgs_cpp