bluez-async 0.2.1

New features

• Added TX power and address type to DeviceInfo.
• Added methods for using a specific adapter rather than all adapters on the system.
• Added support for reading and writing characteristics and descriptors from a given offset, and
  explicitly specifying what type of write operation to use.

Other changes

• Wait for service discovery to complete before returning from connect. This should avoid errors
  when trying to look up services on a device immediately after connecting to it.