Add dscore like DER

[boeddeker]

In #97 it was mentioned, that dscore calculates the DER differently to md-eval-22.pl, if no uem file is given:

• md-eval-22.pl: Choose the scoring region, such that it starts with the first reference and ends with the last reference.
• dscore: Score everything. Implementation: Create an uem with the scoring regions to be the smallest start in ref and hyp and the end is the last time in ref and hyp.

Additional bugfix:

• md-eval-22.pl ignores the uem files, if the filenames/session_ids contain dots
• dscore fails with a lengthy error

ToDO:

• Disable the dscore code and use only md_eval to mirror what dscore does. The dscore code doesn't work with numpy 2