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/ConductorsWatch/build.gradle

@@ -3,8 +3,11 @@
 buildscript {
     
     repositories {
-        google()
+        maven {
+            url "https://maven.google.com"
+        }
         jcenter()
+        google()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:3.0.1'
@@ -17,8 +20,11 @@ buildscript {
 
 allprojects {
     repositories {
-        google()
+        maven {
+            url "https://maven.google.com"
+        }
         jcenter()
+        google()
     }
 }