Provider

New

• new parameter onDevice on the listen method enforces on device recognition for sensitive content
• onSoundLevelChange now supported on iOS
• added compile troubleshooting help to README.md
• SpeechToTextProvider is an alternate and simpler way to interact with the SpeechToText plugin.
• new provider_example.dart example for usage of SpeechToTextProvider.

Fix

• on iOS handles some conflicts with other applications better to keep speech working after calls for example