Add function to get local image file uri from disk cache.

[banli17]

CameraRoll.saveToCameraRoll can save image to local ， but android need a URI, such as "file:///sdcard/img.png"。
can react-native-fast-image get this uri？ like react-native-img-cached

[tonyhb]

It can on master. @DylanVann can we get a 4.0.1 with this in? I have to use 3bcb02219c75195fc69cf6cdff9faebedae9338e in my package.json right now.

Thanks :)

[DylanVann]

In the case of file: or content: urls FastImage will fall back to using Image. This is included in the current version on npm, v4.0.8.

edit: oh, I think that's not actually what you want. @tonyhb that should work for you though.

I can look into providing this. PRs are welcome.

[bichocj]

Thanks; this feature is I was looking for; thanks in advance

[nes123]

will be great to have this feature

[tryanbot]

anyone know is this feature finally released or not?