change to enable this library to run in background threads and processes

[JeanRintoul]

After trying to run this library as well as a web gui front end I realized that the bluetooth cannot possible run in a thread, process, child sub process and the problem is fixable by adding the following lines to the provider.py initialize function in the CoreBluetoothProvider class.

    dispatch_queue = libdispatch.dispatch_queue_create(b'q', None)

    self._central_manager.initWithDelegate_queue_options_(self._central_delegate,
                                                          dispatch_queue, None)

More details can be seen from this stack overflow post:
https://stackoverflow.com/questions/48958267/how-can-i-use-corebluetooth-for-python-without-giving-up-the-main-thread?fbclid=IwAR3X9aaK4kAu-BKFJ3yFDM48CMxiJQmw39GhDxnWeXpxKNKnCNUNOzYSZpk

Merging this in will make the library much more robust for a range of application where the bluetooth runs in the background.

[seanngpack]

@JeanRintoul
Could you provide some insight on how you achieved threading with your main loop and this library?
I'm trying something similar where I have a main loop perform some actions, then ask my Arduino to perform a task, wait for that task to finish, then continue on the main loop.

I'm mainly confused on the docstrings in provider.py saying you can omit the self.ble.run_mainloop_with() method if you're running a GUI or application where you have a main loop. But how does your CoreBluetoothProvider object have the needed information (self._user_thread = None) if you're not using this method?

Nevermind, got it. Instead of running ble.run_mainloop_with() I created my own thread.

[dhalbert]

This library has been deprecated. Please update to use this new library:
https://github.com/adafruit/Adafruit_Blinka_bleio
PR's can be submitted to the new library.