2.0.0

To use 2.0.0 and beyond please update your import to:
import { SimpleStepper } from 'react-native-simple-stepper';

I refactored the internals with the following improvements and updates:

• smaller components
• remove @1x assets
• improve readability of update props
• update demo
• update usage
• move away from unnecessary state variables value and stepValue
• move everything into src directory