Fix code ident
Refactor ECPN_hnodes_pol_v4_back
More hnodes_pol refactoring
Speed optimizations in hnodes_pol
Eliminate nnz() and sum() where possible

Rewrite with any(), all() or find(,1)
Small speed gain expected
Don't handle fully reliable connected graph

Shouldn't get it, so leave only assert(), just to be sure.
Optimize GetIndexedChain