Fix join of DQD results for compare

[MaximMoinat]

This caused mismatches in the join of concept level checks.

@elena: another issue I encountered is that the script gives an error if there are no differences between the DQD results (as in combined_results is empty after the filter)

[MaximMoinat]

While doing a general code cleanup I encountered another issue:
Normally passes are darkblue, fails chocolate1. However, when all checks pass, the passes become chocolate1. @egarcialara Any idea?

[egarcialara]

While doing a general code cleanup I encountered another issue:
Normally passes are darkblue, fails chocolate1. However, when all checks pass, the passes become chocolate1. @egarcialara Any idea?

I think this is because the colors are given as a list, so usually Fails takes chocolate1, but if there's no Fail, Pass takes it as first in the list. I'll make an edit about it! (See #7 )

[egarcialara]

@elena: another issue I encountered is that the script gives an error if there are no differences between the DQD results (as in combined_results is empty after the filter)

Solved in #8

[egarcialara]

After merging the two dependent PR, this can be solved :)