Modify fltinv.f
Modify fltinv.f

1. Add shear stress constraints resolved onto faults.
2. Better error checking: look for underdetermined matrix
   equation, magnitude of inverted fault displacements.
3. Add verbosity levels.
4. Increase maximum input faults, observations.

mherman09/Hdef,mherman09/Hdef,mherman09/Hdef