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.
FYI, you don't _need_ to write out the xpaths first and then call ZU.xpathText. You can just write the string into the call. If that's what you prefer, fine by me.