- `EachRule`
- Made `Validator` a callable class
- Allow adding rules via `Validator` constructor

Deprecated
- `Validator.build()`

Changed
- Moved all files to src folder. Use `import 'package:flrx_validator/flrx_validator.dart';` *BREAKING CHANGE*
- Minor Code cleanup

Fixed
- Fixed `transformMessage` not applying properly in `AnyRule`

Removed
- OneOfRule (deprecated in v0.3.0)

Merge branch 'release/0.4.0+2'