ref #27 -new gradle and sdk version

- added faster bpm estimation by using multiple windows now
- implemented a simple z score based outlier detection
- some ugly heuristics to prefend to many -1 on the screen
NOTE: this is a very unstable version of the code, very protoype

android/ConductorsWatch/build.gradle

@@ -10,7 +10,7 @@ buildscript {
         google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.0.1'
+        classpath 'com.android.tools.build:gradle:3.1.2'
         
 
         // NOTE: Do not place your application dependencies here; they belong