xterm 2.2.0 on Node.js NPM

Xterm.js 2.2.0 is a generally uneventful release, except for the fact that we started 📢 migrating the code base to TypeScript.

📢 Started migrating the code base to TypeScript (#296, #353, #355, #370, #371, #372, #383, #392)
Added ttyd to real-world uses 🎉 (#347)
Documentation improvements for the open, scroll and title events (#351)
Implemented the ^\ string terminator (#377)
Further improvements in the scroll back feature introduced in 2.1.0 (#379, #367)
Cleaned up license declaration in the documentation (#388)
Fixed browser jumping issues when focusing on xterm (#391)