cachable image

[jjhesk]

can this make it easy for cache image?

[anhreg]

There is already a great package https://github.com/wcandillon/react-native-img-cache for handling cache.
I think there should be a props to switch on off between using and at line 101 in TransformableImage.js
Not much to implement but it makes this package to depend on react-native-img-cache. Please consider.