Custom bed

[replikation]

Done

• fixed Varskip2 primer not working for Variant calling doesn't seem to work with VarSkipV2 #210
• adding custom bed files for medaka
• adding custom bed files for nanopolish
• covarplots for custom bed files

input via --primerV primer.bed

[replikation]

@hoelzer if working via singularity on your end ill merge and build up a release. did not identify any bugs while testing all possible run options. this PR contains also #208

[hoelzer]

@replikation works! Feuer frei