Correctly update record button in AudioRecorder example.

The record/stop button should have a "Record" text when QMediaRecorder
has the LoadedStatus.

Change-Id: I677845382b24ecf1f2351fc8e1e2e182b2c8d548
Reviewed-by: Christian Stromme <christian.stromme@digia.com>
Fix crash in QCameraInfo when no camera is available on the system.

Change-Id: I04bea9d6afcf567c64788c3765cc6626dc9cd482
Reviewed-by: Christian Stromme <christian.stromme@digia.com>
Doc: Qt Audio Engine: Restore lost docs

When QDoc stopped accepting the version number of QML modules, some
parts of QML documentation disappeared silently.

Change-Id: I528a2d77587e5803ed971dfe8849d0b37d9c555a
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>
Android: fix QMediaRecorder failing to start in some cases.

Because camera operations are performed in a dedicated thread, starting
a recorder was sometimes failing because the camera was not yet ready
(unlocking it was not done yet). Camera locking and unlocking are now
synchronous operations.

Change-Id: I92c3c2f3666b63e7451e4ee1ab89dcbc85ae6c24
Reviewed-by: Christian Stromme <christian.stromme@digia.com>