Readme tweaks.

Add credits.

Drop average masses, for clarity.

Monoisotopic mass conversion.

Update readme.

Shorten default message.

Cleanups, clarity in variables, pep8.

Ultra modularize, add some funny inspect/getattr() methods.

Modularize functions more, python3 conversions.

Fix mass calculation (+h2o), modularize peptide length.

WIP: hackjob, but maybe working for BS3?

WIP commit, added memoization caching.

General cleanup / WIP commit.

Readme / cleanups.

Combinations mostly implemented.