Petsc 3.5.2

Update PETSc to the newest version.
Add numerous dependencies (metis, parmetis, scalapack, mumps, superlu_dist)
and options (compex/real).

Closes #1298.
GetDP: stable incompatible with PETSc/SLEPc 3.5.2

- Temporarily fail if building stable against PETSc/SLEPc
- Update sha1
- Update PETSC_ARCH / SLEPC_ARCH.