Site specific features

Two commits for site specific stuff:

- sitename was broken on some sites where the separating "-" is no longer present (e.g. "tag - my question - Android Enthusiasts Stack Exchange"), while some others kept it ("whatever - Area 51 - Stack Exchange"). So both checks/replacements are needed (see comments, which I left for future reference, and suggest to keep in the code).
- introducing a new "$MYUSERID$" placeholder for e.g. links to other on-site questions, which gets replaced by the logged-in user's ID to earn him some badges for his work