This alters the logical used in PetscNonlinearSolver to:

1. Not free the SNES instance between solves
2. Use SNESReset by default in between solves
3. Add two new options "reuse preconditioner" and "reuse preconditioner maximum iterations" to support preconditioner reuse

Fix failing tests by changing SNESReset back to old behavior of
calling the custom _snes destructor.

Use getter/setter to supply the required properties for the new reuse
capability.  Default to libmesh_not_implemented() in superclass,
implemented in the petsc solvers.

This fixes an error I introduced in passing the value of the
maximum iterations to the monitor.  The storage there needs to
persist across multiple solves with the same solver.