[Fix] sampleData: fix calculation of badseries

Signed-off-by: oleg komarov <o.komarov11@imperial.ac.uk>
[Rename] Nbad is Nbadtot with selection and bad obs

Signed-off-by: oleg komarov <o.komarov11@imperial.ac.uk>
[Add] Tests: graph with incremental sel, filter, consolidation steps

Signed-off-by: oleg komarov <o.komarov11@imperial.ac.uk>