initialize some variables as complained by nightly tests

add MatView_SeqXAIJ_ASCII_structonly(); enable A->structure_only in MatSetValuesBlocked_SeqBAIJ

bugfix for MatDuplicateNoCreate_SeqBAIJ()
Reported-by: Adrian Croucher <a.croucher@auckland.ac.nz>
Mat->ops cannot be copied to new matrix because original mat's ops may have been modified, e.g., by

bugfix for MatDuplicateNoCreate_SeqBAIJ()
Reported-by: Adrian Croucher <a.croucher@auckland.ac.nz>
Mat->ops cannot be copied to new matrix because original mat's ops may have been modified, e.g., by matcreatesubmatrices.

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add 'structure_only' to seqbaij matrices -- MatView() does not work yet

rm MatLUFactorNumeric_SeqBAIJ_11_NaturalOrdering() because it does not improve performance
add MatSolve_SeqBAIJ_bs_NaturalOrdering(), bs=12,...,14
add test runex50_2

experiment PetscKernel_A_gets_A_minus_B_times_C_11

add timer to MatLUFactorNumeric_SeqBAIJ_11_NaturalOrdering()

test new A = A*B

implement MatSolve_SeqBAIJ_11_NaturalOrdering

implement PetscKernel_A_gets_A_times_B_11()

fix duplicate definitions warned by -Wredundant-decls

Also a bugfix? BLASdotu_ -> dotu

Reported-by: Till Martens <till.martens@dlr.de>

Merge branch 'master' of bitbucket.org:petsc/petsc

Minor fixes for tchem examples due to changes in PETSc infrastructure

rename struct Mat_SubMat -> Mat_SubSppt

rename MatGetSubMat -> MatCreateSubMat

Merge branch 'hzhang/fix-getsubmats-reuse'

cleanup

bugfix for memory error as reported by nightly tests

typo

bugfix as reported by nightly test src/mat/examples/tests/runex86_3;
removed MPI_Allreduce() and MPI_Scan() calls by using output of inline function

fix warnings reported by nightly tests

fixbug for MPIBAIJ

reorganize/rename MatDestroy_xxx_SubMatrices

additional fix

bugfix for MatCreateMPIMatConcatenateSeqMat_MPIBAIJ
Contributed-by: Lawrence Mitchell <lawrence.mitchell@imperial.ac.uk>