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 overwriting of BDDC weights.
Merge branch 'master' into 1.8.0_master
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
Analytical solution for transport problems.

- preliminary text incorporated into documentation
Merge remote-tracking branch 'origin/JSI_bddc'
Merge branch 'master' into 1.8.0_master
Merge branch '1.8.0_master' into JB_finish_fieldset
Temporary fix for wrong ASSERT.
Introduce FlagArray.

- bitfield like class that allows setting and testing
  arbitrary subset of bits.
Introduce FieldFlag class.

- this class just defines FlagArray type used by Field classes
  and common Masks to set and test
- in order to make these masks easily accesible from FieldSet, we make
   FieldSet descendant of FieldFlag
- add FieldCommonBase::flags() getter