iOS SDK is dependent on using MetaWearScanner to connect to devices

[andreasmpet]

Hi!

I'm currently in the process of implementing a flutter-wrapper around your sensor fusion sensors that are available in the MetawearRL board.

While doing that I noticed to my dismay that the iOS sdk requires you to do the BLE scanning via MetaWearScanner because of the circular dependency between the MetaWear and the MetaWearScanner, whereas the Android-sdk leaves the Bluetooth scanning up to the user.

I understand that you want to make the library accessible for people who are not familiar with the CoreBluetooth, but I think the tight coupling between the MetaWearScanner and the MetaWear class is very limiting to how you can use your SDK.

I hope you'll consider to do something about this limitation in the future.

Cheers!