Changes:
- Beta version of SNMPd interface
- An alert by e-mail can be sent when a connection is down
- Update Shadowsocks to release 3.2.1
- A banner display when a new version of OpenMPTCProuter is available
- Many fixes
OpenMPTCProuter VPS v0.64:
- Update to MPTCP kernel 4.14.79
- Support Ubuntu Server 18.04
- Update Shadowsocks to 3.2.1
