Build instructions lack typescript/tsc

```
Update codejar

> codejar@4.2.0 build
> tsc

sh: 1: tsc: not found
make[1]: *** [makefile:58: codejar] Fehler 127
make[1]: Verzeichnis „/home/schubert/workspace/decker/third-party“ wird verlassen
make: *** [makefile:21: upgrade-third-party] Fehler 2
```

Solved by `npm install typescript`.