v3.8.0-beta2

What's Changed

• Up to version 3.8.0-beta2 by @fmjsjx in #123
• Speed up buildscript by @fmjsjx in #124
• Upgrade netty to version 4.2.0.RC2 by @fmjsjx in #125

Full Changelog: v3.8.0-beta1...v3.8.0-beta2