Updated some external in user docs.
merged from paulette
Merge pull request #1869 from naylor-b/docs

doc changes from paulette
fixed an issue with bidirections connections to/from a subdriver
Merge branch 'mpi' of github.com:Kenneth-T-Moore/OpenMDAO-Framework into mpi
Merge branch 'mpi' of github.com:naylor-b/OpenMDAO-Framework into mpi
Speedup for adjoint Linear GS