Zmatrix information output and re-starting options (+fixes)
The program now writes a summary of the zmatrix *explicit* variables
at each step of the optimization phase.
New option MD.UseSaveZM added to preserve Zmatrix information accross runs.
New zmatrix test.
Other fixes:
- Remove comment from optim.F implying that it does not work for variable cell
relaxations.
- Fix computation of lattice angles in wxml/flib_wcml.f90.