Filter languages by whitelist and/or blacklist
Add tests for whitelist and blacklist
Update Readme
Merge branch 'kamilbielawski-languages_whitelist_and_blacklist' into feature/add-white-and-black-list
Refactor code-style in useage example in Readme.md
Move description of undefined languages in Readme.md
Remove competition from Readme.md
Refactor API

- Refactor style;
- Add performance improvement when neither whitelist nor blacklist
  are given.
Refactor comment line-wrap in API
Refactor tests
Merge branch 'feature/add-white-and-black-list'

- Add support for options;
- Add support for `options.whitelist`, when given, only languages
  listed in `whitelist` are detected;
- Add support for `options.blacklist`, when given, languages listed
  in `blacklist` are never detected.
Update changelog for 0.3.0
0.3.0