Add spec for pre- and suffix punctuation in words
Add docs for pre- and suffix punctuation in words
Add functionality for pre- and suffix punctuation in words

- Refactor `mergeInnerWordPunctuation`;
- Add support for prefix punctuation;
- Add support for affix punctuation;
- Add ampersand to list of inner word punctuation;
- Fix detection of multiple inner word punctuation marks
  in between words.
Update changelog for 0.1.2
0.1.2