HiCUP report di-tag size plot

[StevenWingett]

Add calculated lengths to X-axis of size plot. Also set the starting zoom to something sensible.

[StevenWingett]

Actually, it appears that t

here is some very rare event that causes some di-tags to be predicted to have a negative length. (see attached report).

In practical terms this is not going to affect results in any meaningful way.

SRR6726678_1_2.hicup.bam.HiCUP_summary_report_OcbeopcVKI_01-39-13_16-06-2021.html.zip

[StevenWingett]

Suggestion - change the very few negative values to 0