Use proguard to remove logging on release

proguard-logs.txt

# Optimization needs to be turned on to remove logs
-assumenosideeffects class android.util.Log {
    public static boolean isLoggable(java.lang.String, int);
    public static int v(...);
    public static int i(...);
    public static int w(...);
    public static int d(...);
    public static int e(...);
    public static int wtf(...);
}
-assumenosideeffects class com.orhanobut.logger.Logger {
    public static Printer t(...);
    public static void log(...);
    public static void v(...);
    public static void i(...);
    public static void w(...);
    public static void d(...);
    public static void e(...);
    public static void wtf(...);
    public static void json(...);
    public static void xml(...);
}