[petsc-users] For users of PETSc master branch, API change

[Barry Smith]

   For users of the PETSc master branch.

   I have pushed into master some API changes for the PetscOptionsGetXXX() and 
related routines. The first argument is now a PetscOptions object, which is 
optional, if you pass a NULL in for the first argument (or a PETSC_NULL_OBJECT 
in Fortran) you will retain the same functionality as you had previously.

   Barry