retag presumed processing artifacts in HNCO spectrum due to lack of corresponding crosspeaks in NHSQC
add 'backbone amide' tag to remaining HNCO peaks that have 0 tags (although some may in fact not be legit backbone amide peaks)
retag HSQC peaks b/c:

 1. no HNCO crosspeaks
 2. seem to be processing artifact

also retag group of HSQC/HNCO peaks that appear to be a tryptophan sidechain
asparagine/glutamine sidechain peaks in NHSQC/HNCO:

 - merge multiple spin systems into 1, deleting the others
 - retag peaks
asparagine/glutamine sidechain peaks in NHSQC/HNCO:

     - merge multiple spin systems into 1, deleting the others
     - retag peaks
identify sidechain arginines by split-peak pattern; merge spin systems and retag peaks; also add two unpicked NHSQC peaks