The changes to RichText.js seem fine, although independent of the main changes.   It's just supporting the textDir flag (except for textDir=auto) in the Editor, right?

Please submit as a separate pull request with a small automated test.

Also, seems like isTextDirLeftToRight() could be reduced to a single line, like isLeftToRight():

```
return this.textDir ? (this.textDir != "rtl") : this.isLeftToRight(); //Boolean
```