Fix missing util mod. Constricted warnings

- Util.rs was missing from list. It is added now
- In an effort to make compiler more strict, the wanr on managed heap
  memory was added.
Remove field delimiter.

- There is currently no need for it. Further more, it causes error on
  Rust 0.8 so it was removed.
Update doc

- Fix all docs to end on 80th character regardless of indentation
- Remove end of line whitespace on some of docs
Implement parser

- Update the parser implementation. Added parsing for outside or inside
  tags.