Read library spectra from various library formats: - [X] Full SpectraST support (sptxt). - [X] Mascot Generic support (MGF). - [ ] BiblioSpec support (blib). See #2. - [ ] Encyclopedia support (elib, dlib). See #12. - [ ] Spectronaut support. See [Spectronaut demo data](https://biognosys.com/resources/spectronaut-demo-data-set/).