add captureScreen

ViewShot is the default export so update the docs

ctx https://github.com/gre/react-native-view-shot/issues/67

TextureView compatibility on Android as per Issue #57

As per owner's suggestion:
Firstly get all children recursively;
Then check if each child is an instance of TextureView with instanceof;
Make sure child knows it's not opaque and get its bitmap into a buffer;
Draw said bitmap into the current canvas.

This assumes that these TextureView elements are ordered in the tree.

Update Android dependencies

Remove override of 'createJSModules' for RN 0.47

Add podspec for CocoaPods support

Save the picture to the album to broadcast the album refresh

Fix iOS Hang by Using Proper Method Queue

fix(RNViewShotModule): FileNotFound exception

My previous commit didn't fixed issue with nested paths, so this commit fixes it.

recursively create folders before creating file