Merge changes Iba73140f,Id8481b87,I87afde2b,I5f34aaf9,I33f93326, ...

* changes:
  floss: Add GATT raw tool to btclient
  floss: Move callback handlers away from main.rs
  floss: Synchronize readline with foreground action
  floss: Refactor create_adapter_proxy
  floss: Update TODOs
  floss: Handle service_changed callback