small fixes

Hg-commit: 15fc3499cf02f49190f576669860cdb9b667729c
fixed typo in changes file

Hg-commit: 8a4db97ecc8083c4fc4c69987e3b4887a93dc033
fix typo

Hg-commit: 6f07201d3181c1219607fb2f005e85a523e506c5
SNES ex12: Fixed output and preparing for Neumann problem

Hg-commit: 80af08fbb63450ee85481f58bc722b97bf4164db
SNES ex12: Added Neumann test

Hg-commit: b6437cb99986d306f15e3d0d52a31ee228232ae1
DMPlex: More work on labels for submeshes
 - Added DMPlexLabelComplete()
 - DMLabelCohesiveComplete() --> DMPlexLabelCohesiveComplete()

Hg-commit: 8bacd3bc20547e9943d7b860c66dbdb96c251fc6
DMPlex:  Fixed memory leak in viewer

Hg-commit: 66be6c10973eb62685f421681c83e86b3d66c44c
added guards for PC UseAmat in PC_MG.

Hg-commit: 2fc7fd9974d23a05132e51224a8f8fa2b2c835ee
SNES ex52: Upgraded to new interface and fixed output of all 2D tests

Hg-commit: 786cb6ce21ece98509c94ee6d16eb27f6cf97e0f
Builder: Allow --testum to take a list

Hg-commit: 94a6ca27f413d7d39c531c64539a39441b125dea
SNES ex52: Fixed output for 3D tests

Hg-commit: ec7ed1f6c6a3a4eb5cad599ea66f8d24ae0bd345
rename 'adapt_' back to 'est_' for Chebyshev; bugfix for option "-ksp_chebyshev_estimate_eigenvalues_radom" as reported by [petsc-maint #155733] petsc-dev: disappearing options prefix in kspchebyshev

Hg-commit: f633d63d3df398113de0afcb55d828823a1ad3c3
DMPlex: Moved out Preallocation and FEM support to other files

Hg-commit: b2561291e574ff9a0f8a073426e136d4a44a4dde
trying to get logic right for use_amat in PC_MG

Hg-commit: 1603136e55b5b4ab324948f552c421772fa7023a
TS ex9bus: Fixed MatSetValues argument

Hg-commit: 4561ec88783f9573d3ba410a26b5a930e71c8739
Updated the ODE equations to match with Henry's results.

Hg-commit: 6e0ddc6e9b6d8a9d8eb4c0ede0105827a6b58dfb