BLE throughput with MTU size exchange
1. Support mtu exchange
2. support loopback, ack and no responese test mode for Android 5.x to 6.0
3. Added BLE device interval time change
4. UUID list:
UUID_SERVICE_BLE_DEVICE_INTERVAL = UUID.fromString("0000e050-0000-1000-8000-00805f9b34fb");
UUID_CHAR_BLE_DEVICE_INTERVAL = UUID.fromString("0000f050-0000-1000-8000-00805f9b34fb");
UUID_SERVICE_BLE_THRUPUT_TEST = UUID.fromString("8832ab08-ba2d-0184-004c-68c08e2190bf");
UUID_CHAR_BLE_THRUPUT_TEST_WRITE = UUID.fromString("361e118a-5524-29b6-0345-b15e12e25b34");
UUID_CHAR_BLE_THRUPUT_TEST_LB = UUID.fromString("361e118a-5524-29b6-0345-b15e12e25b34");
CLIENT_CHARACTERISTIC_CONFIG = "00002902-0000-1000-8000-00805f9b34fb";