Chage ConfigEnv behavior to raise when option or default are undefined.
Add Repository classes.

This is a first step into unifying all Config classes.
Remove unused variables
Add comments
Unify Config classes into one.
Fix RepositoryEnv logic
Fix typo
Adapt AutoConfig to use Repositories with Config.
Fix tests to use Repositories
Refactor tests to use fixtures
Update README
Fixing landscape reported issues.
Fix more landscape reports
Add badges to README
Bump version to 2.2
Merge pull request #4 from henriquebastos/undefined

Version 2.2