* format place_tracker README
* update sentence in README
* sort Dart members, remove unnecessary type declarations
* Run place_tracker on Android and iOS, update project files
* add link to developer preview caveat
* grammar
* update MAINTENANCE
To use this plugin on iOS you need to opt-in for the embedded views preview by adding a boolean property to the app's Info.plist file, with the key io.flutter.embedded_views_preview and the value YES.
<key>io.flutter.embedded_views_preview</key>
<true/>
