2.18.0-rc

- format: "base64" || "file"
- type: "png" || "jpeg"/"jpg" || "webm" (android only)
- quality: from 0 to 1 (iOS support only with type=jpg/jpeg)
- filePath: for format=="file" you must provide a file path (you can use react-native-fs to get directory constants)

Attempt to fix #38

See https://github.com/ProjectSeptemberInc/gl-react/issues/38

Add profiling for render method

Bugfixes and Features of 2.17.x