[WIP] library spectrum output for msfragger

[trishorts]

MSFragger has an alternative style spectrum library format library.tsv with the bellow example. This PR creates a new ToString method for LibrarySpectrum with this alternative format.

[codecov]

Codecov Report

Attention: Patch coverage is 98.18182% with 1 line in your changes missing coverage. Please review.

Project coverage is 77.81%. Comparing base (8cea9fc) to head (abc8d4a).

Files with missing lines	Patch %	Lines
mzLib/Omics/SpectrumMatch/LibrarySpectrum.cs	98.18%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #840      +/-   ##
==========================================
+ Coverage   77.77%   77.81%   +0.03%     
==========================================
  Files         229      229              
  Lines       34140    34194      +54     
  Branches     3537     3544       +7     
==========================================
+ Hits        26554    26607      +53     
  Misses       6983     6983              
- Partials      603      604       +1     

Files with missing lines	Coverage Δ
mzLib/Omics/SpectrumMatch/LibrarySpectrum.cs	95.57% <98.18%> (+2.35%)	⬆️

🚀 New features to boost your workflow:

• ❄ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.