remove old fonts, enable proguard

android/app/build.gradle

@@ -96,7 +96,7 @@ def enableSeparateBuildPerCPUArchitecture = false
 /**
  * Run Proguard to shrink the Java bytecode in release builds.
  */
-def enableProguardInReleaseBuilds = false
+def enableProguardInReleaseBuilds = true
 
 /**
  * The preferred build flavor of JavaScriptCore.