responsive 0.2.0

Allow to easily build a responsive Flutter UI

[0.2.0] - New components

- Refactoring with some name changes
- Add new Responsive class to calc Size, Offset or number of columns
- Redo example app and remove examples dir
- More documentation and add some media

[0.1.5] - Cleanup

[0.1.4] - Refactoring of the FlexibleWidget

[0.1.3] - Little change

[0.1.2] - Very Changes

- quit some logs

[0.1.1] - Very Changes

- add documentation

[0.1.0] - Very Changes

- add different configurations for landscape and portrait
- add Offset configurations.
- add Offsets for landscape and portrait too.

[0.1.0] - Very Changes

- add different configurations for landscape and portrait
- add Offset configurations.
- add Offsets for landscape and portrait too.

[0.0.9] - Comments corrections

- Little  corrections

[0.0.8] - Comments corrections

[0.0.7] - Comments corrections

- Little comments correct 

[0.0.5] - Example Readme correction

[0.0.4] - Example Readme correction

[0.0.3] - Example Readme correction

[0.0.2] - Example Readme correction

[0.0.1] - initial release

- Allow to make responsive UI with Flutter easily