Merge remote-tracking branch 'origin/master' into JSI_bddc

Conflicts:
	src/flow/darcy_flow_mh.cc
Merge branch 'JSI_bddc' of github.com:flow123d/flow123d into JSI_bddc
Fix memory leak in LinSys_PETSC::gatherSolution

- need not to call VecCreateSequential, vector created by VecScatterToAll
- improve bin/valgrind.sh, allows passing additional parameters to valgrind

close #112
Fix overwriting of BDDC weights.
Merge branch 'master' of github.com:flow123d/flow123d into JSI_bddc
assemble diagonal weights in BDDC

- instead of creating a map with the weights, register them in the
  linsys and then assemble this matrix for loading to BDDCML