Reset seqlet coordinates with respect to "--window"

[jvierstra]

The seqlet coordinates (per example) are returned relative to the "trimmed" contributions For example, if the user specificies a window of 100 with the "--window" argument, on a full sequence input width of 100 then the return seqlet coordinates, then the seqlet coordinates should be shifted by 450 bp when saving to the file MODISCO output file.

Alternatively, this could be just documented. I was trying to use the H5 file (after backwards conversion) to call seqlet hits on the examples and this messed me up for a couple of hours.