Add 3' End and Full Fragment options to TagPileup

[owlang]

For some datasets (like single-end RNA types, because of the reverse transcriptase), the 3' end is the important marking point which Tag Pileup currently cannot do. Other studies analyzing datasets have been processed with the full imputed length of the fragment and we would be like to mimic this behavior in Tag Pileup.

This ticket specs out implementation of these new features.

Break "Read Output" into two groups of radio button selections:
"Read Aspect" (4 options) = 5' End, 3' End, Fragment Midpoint (require PE), and Full Fragment (require PE)
"Read Output" (3 options) = Read 1, Read 2, All Reads

...where "Read Output" is unavailable for selection when "Read Aspect" = Fragment Midpoint or Full Fragment.

If we map old behavior to new behavior,
old Read 1 = 5' End + Read 1
old Read 2 = 5' End + Read 2
old All Reads = 5' End + All Reads
old Midpoint = Fragment Midpoint (require PE) + NA

The new options without analogous old behaviors are selecting the 3' End of Read 1, Read 2, and both reads along with the Full Fragment (require PE) option.