Adding DMMoab and VecMoab, along with various examples and tests.
Changes suggested by Matt in pull request.
Changes suggested by Jed and Barry.
Fixing compile error in dmmoab.
Fixing uninitialized memory, and adding output.
Merge branch 'master' into tautges/dmmoab

Obtain config/BuildSystem as subtree.
Add .gitignore
Merge branch 'maint-3.2' into maint (add .gitignore)
Merge branch 'barry/matload-mpiaj-bugfix-maint' into maint
VecView_MPI_HDF5_DA: remove unused variable
Merge branch 'maint'

Conflicts:
	src/mat/impls/aij/mpi/mpiaij.c
Fix for SNESSetConvergenceHistory() when input a is null
Merge branch 'barry/convergence-history' into next
more work on moving AMS model to viewer
Merge branch 'barry/convergence-history' into barry/ams
DMPlex: Added F90 interface for DMPlexComputeCellGeometry()
Merge knepley/plex into next
changed AMS publishing to use the Viewer model
added simple AMS viewer for mat,ksp,snes,ts
added --ksp/snes/ts_view_pre for starting the viewer before the solve (ugly but useful for AMS)
added PetscStackCalls around AMS function calls when appropriate (note do not want these in webserver because do not webserver stopping just because AMS server is down
Merge branch 'barry/ams' into next
builder2.py: python syntax and sys.executable