Yalexs-ble

Fix
* Detect missing characteristics and clear the cache ([78](https://github.com/bdraco/yalexs-ble/issues/78)) ([`e921bf0`](https://github.com/bdraco/yalexs-ble/commit/e921bf009120d980a2502288cb006e2421396ddb))

Feature
* Add YaleXSBLEDiscovery class to be able to get discovery data from august cloud ([77](https://github.com/bdraco/yalexs-ble/issues/77)) ([`28da7da`](https://github.com/bdraco/yalexs-ble/commit/28da7dad7e52c80182f3b938de0eb9fda07f51b7))

Fix
* Improve operation reliability ([76](https://github.com/bdraco/yalexs-ble/issues/76)) ([`91f403f`](https://github.com/bdraco/yalexs-ble/commit/91f403f0fa6ace9bdfec6f5bd0694bbc124b84f0))

Fix
* Drop connection instead of executing shutdown ([75](https://github.com/bdraco/yalexs-ble/issues/75)) ([`6d85edf`](https://github.com/bdraco/yalexs-ble/commit/6d85edfa2ac4286a5b05582907f19119939c6a71))

Fix
* Un-retrieved future exceptions when canceled ([74](https://github.com/bdraco/yalexs-ble/issues/74)) ([`9c704dc`](https://github.com/bdraco/yalexs-ble/commit/9c704dc77b7791493d42621f77bbf3c51e87e75f))

Fix
* Lock advertisement state needs to be reset after going unavailable to ensure it becomes available again ([73](https://github.com/bdraco/yalexs-ble/issues/73)) ([`cc1a252`](https://github.com/bdraco/yalexs-ble/commit/cc1a2529b4dd6406b71290bb83ec71fc9816cc51))