Update beck-online.js

1. beck-online.js
Added support for beck-online "Leitsatzkartei" LSK (database of leading records), i.e. scraping of articles where beck-online does not have the article itself but only information about the article

2. juris
Added new translator for the German legal database Juris.
nit: you can simplify this as
```
else if (matchSrc = mySrcString.match(/^([^,]+)\s(\d+)\s*,\s*(\d+(?:-\d+)?)\s*\((\d{4})\)\s*$/)) {
  newItem.issue = matchSrc[2];
  ....
```