puhh. this is a big commit

- change the complete file sending / receiving process between phone and watch, we now use channels instead of simple messages. this is recommentad by google, due to some changes in google play services.
- made some smaller changes in the ui, for file saving and saving of sensordata for evaluation purposes
- edited the manifest and gradle script for play store.
- made some change for a better performance for he huawei watch

android/ConductorsPhone/app/src/main/AndroidManifest.xml

@@ -3,13 +3,12 @@
     package="de.tonifetzer.conductorswatch">
 
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
-    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
 
     <application
         android:allowBackup="true"
         android:icon="@mipmap/ic_launcher"
         android:label="@string/app_name"
-        android:roundIcon="@mipmap/ic_launcher_round"
+        android:roundIcon="@mipmap/ic_launcher"
         android:supportsRtl="true"
         android:theme="@style/AppTheme">