public static void init(int logLevel) {
        init(new LogConfiguration.Builder().logLevel(logLevel).build(),
                DefaultsFactory.createPrinter());
    }
Initialize log system, should be called only once.

@param logLevel the log level, logs with a lower level than which would not be printed
android/android_framework/base/src/main/java/com/elvishew/xlog/XLog.java