Added alternative characteristic read/write callbacks that carry the connection description information.
Fixesh2zero/NimBLE-Arduino#83
Author: lknop <lknop@users.noreply.github.com>
* Get service handles on server start
* remove service + indicate service changed
* Reset gatt services when no connections active and services changed.
* NimBLEServer::createService can now be used any time and will send service changed
indication if server was already active.
* Add ability to remove advertised serviceUUIDS
* Adds addService() method to server to be allow user to re-add a service previously removed
* Add destructior to NimBLEServer, NimBLEService and NimBLECharacteristic to release allocated resources.
