minus sign

- there should be "-" sign in -C - B(A^-1)B in generation of interface
weights for BDDC
- this seems to improve convergence of BDDC for 1D-2D-3D cases
response to issue #92

Cleaning the interface to BDDCML.
A bug fixed in creating diagonals for interface weights for BDDC.
missing header
Merge branch 'master' of github.com:flow123d/flow123d into JSI_bddc

completed merge of master into JSi_BDDC

Conflicts:
	src/flow/darcy_flow_mh.cc
	src/la/linsys.hh
implemented missing routines for BDDC

mat_zero_entries
rhs_zero_entries

NODE macro avoided in bddcml_wrapper
added comments
update to BDDCML v 2.4
HOME variable
update CMake installation script

- download BDDCML 2.4
Merge remote-tracking branch 'origin/master' into JSI_bddc

Conflicts:
	src/flow/darcy_flow_mh.cc
Merge pull request #106 from flow123d/JSI_bddc

JSI_bddc