Allow building a table of internal ions as available in msproduct (part of ProteinProspector). Rework slicing to allow an optional startIndex. This can be used for describing internal ions. Add fully general getSeqMass to Peptide class.
Make internal ion option showing optional.
Fix styling of internal ion table relative to normal table.
Apply more styling fixes to internal ions table.
Initial implementation of displaying internal ions over the spectrum.