Readme updates and style composition.

-Updated readme with examples, gifs, an API reference and a contributing clarification.
-Changed how custom styles were overwritting the local ones, now they should support partial composition (e.g. only providing styles for the container won't clear the styles to the title).
-Added test case regarding styles.
-Added stories handling different styles.

Minor bug fixed and improved coverage version.

-Improves testing coverage and test quality. Resolves #17
-Fixes an unexpected behaviors where internal custom callbacks wouldn't be used in case that event callback were provided as prop.

First release out of beta!

Finally this package can be useful! On this release storybook has been added to aid with development.
On the functionality side, now the input will be able to handle an animated label and custom styles!
This version has been published to npm https://www.npmjs.com/package/react-native-awesome-text-input/v/1.0.1