Recpred suggestions

[bcorrie]

A couple of minor suggestions/questions:

• Reports that don't have sequence_alignments are not generating sequence length histograms. Is that correct? Do you need sequence_alignment to do a sequence length distribution or is sequence sufficient? Not sure, but thought I would ask.
• As mentioned in Repcred PDF report is not very pretty... #34 the PDF report has odd tables, lists, and lots of white space, which makes for a not very "pretty" report
• As mentioned in the meeting today, a bit more explanation on why each of the reports is relevant for testing a repertoire's credibility would be nice. For the inexperienced user, I might not know why you are showing me productive vs non-productive sequences, sequence length distribution, gene usage, and chimerism stats. What do these tell me about the repertoire?

Overall I think it is looking pretty robust and pretty complete.