Fix description of two unit tests
Add spec for better inner word punctuation classfication.

- Add spec for underscores (_) inside words;
- Add spec for question marks (?) inside words;
- Add spec for equals signs (=) inside words;
- Add spec for at signs (@) inside words.
Add spec for a trailing full stop after version number
Add functionality for better inner word punctuation and sentence parsing

- Add undescores (_) to list of inner word punctuation;
- Add question mark (?) to list of inner word punctuation;
- Add equals sign (=) to list of inner word punctuation;
- Add at sign (@) to list of inner word punctuation;
- Rename pre- and suffix expressions to initial and final;
- Add expression for numerical token detection;
- Refactor mergeInnerWordPunctuation;
- Add mergeFinalWordPunctuation;
- Add mergeInitialWordPunctuation;
- Refactor mergeInitialisms;
- Remove support for numerical-only initialisms;
- Refactor some cases of value checking instead of stringifying.
Update benchmark results
Add section on Shakespeare to docs