Fix Android recognizer erratic behavior

This release does not introduce any breaking changes

Bug fixes:

• Android system sometimes reports that a pending intent is still registered, while it is not. Because this kind of behavior cannot be trusted, on start listening, every recognizer will stop itself first if Android reports that is up. This fixes the problem and renews the pending intent each time the application starts.

Enhancements:

• Successive calls to human activity recognizer startListening() method with different start options will lead to the last one being picked as the current one. This allows to easily change recognizer settings (e.g. the recognition interval).