Refactoring: replaces a comment with a meaningful variable name.
Refactoring: Sandi Metz Rule.

5 lines per method are enough.
Better documentation.
To help me maintain the files with 100 lines tops.

For now, the only intelligence is to exclude comments (docs) from counting.
New behavior documentation

One can define the same `from_hash` and `to_hash` behavior for multiple `ivars` if needed.
Separates options from `ivar` names so one can indicate the same strategies to `:from_hash` and `:to_hash` for multiple `ivars`.
Better grouping concerns in the tests, since they are documentation too =)
Introduces `Hasherize.new`

A sugar syntax to include `Hashing` and call `serialize` with options.
[WIP]: nested serialization.