Add L2CAP CoC support (squashed)

[85542e0] fix test
[3748781] add ASAH sink example
[e782e29] add app
[83daa30] wip
[7f138a0] add test
[f732108] allow different address syntax
[9d0bbf8] rename deprecated methods
[eb303d5] add LE CoC support

bumble/gatt.py

@@ -25,6 +25,7 @@
 import asyncio
 import types
 import logging
+from pyee import EventEmitter
 from colors import color
 
 from .core import *