expose a sendRequest function

First off thank you for making this!

Not sure if this is part of your upcoming roadmap but would it be possible to expose a function that would allow us to search for tracks, get specific tracks, get specific albums etc etc? (Similar to lufinkey's react-native-spotify library)

As a quick fix we could manually put in the endpoint we need instead of having to create separate functions for each endpoint within the library. Just something to help create a request would be a nice addition to this library.