[FWR-LmjOd2zc] Refactor of microphone accessibility checker
[FWR-LmjOd2zc] 'isMicrophoneAccessible()' added to external interface.
[FWR-LmjOd2zc] 'isMicrophoneAccessible()' - readme updated
[FWR-LmjOd2zc] RecorderJSInterface: removed redundant `this` statements
[FWR-LmjOd2zc] RecorderJSInterface: `recorder` filed became private, improved order of methods.
[FWR-LmjOd2zc] RecorderJSInterface: event names and internal fields became private
[FWR-LmjOd2zc] RecorderJSInterface: all internal methods became private, added "todos" for further improvements
Merge branch 'feature/FWR-LmjOd2zc' into feature/FWR-j9J3LsxC
Triggering `observing_level_stopped` correctly [Bugfix]

Resolves issue #26 on github
Merged in feature/FWR-LmjOd2zc (pull request #1)

Check microphone accessibility
[FWR-j9J3LsxC] Event extensions moved into separate package
[FWR-j9J3LsxC] MicrophonePermissionPanel: wrapped actions on microphone permission dialog.
[FWR-j9J3LsxC] MicrophonePermissionPanel: 'panel_closed' works with both simple and advanced permission dialog.
[FWR-j9J3LsxC] JavaScript interface: added ability to call for permanent microphone permission.
[FWR-j9J3LsxC] Demo: Improved permission dialog positioning.
[FWR-j9J3LsxC] Readme: Supplemented JS interface description
[FWR-j9J3LsxC] Recorder: minor improvements.
[FWR-j9J3LsxC] Demo: added microphone permission button.
[FWR-j9J3LsxC] SettingsPanelObserver: panel close observation extracted from MicrophonePermissionPanel
[FWR-m3Riri1Z] MicrophonePermissionPanel: Broken unit test

Returned with `Error #1063` without stack trace.