[mythtv-cmyth] Release v1.7.11

This updates the MythTV addon to version 1.7.11.

Changelog:
- Fixed crash when setting up Live TV (in rare cases)
- Fixed issue with not updated recording list (Daylight Saving Time)
- Fixed issue with empty recording list (caused by '[' character)
- Fixed playback of recordings made by a slave backend
- Removed 'Failed to connect to MythTV Backend' notification

+ Some changes under the hood (improve data buffers and mutexes). This does not have any functional impacts, but cleans up some code parts, and might improve performance under certain conditions.