[xml/sgml] Removed some cruft from Alioth page (Forums, Tracker)

[W. Martin Borgert]

Hi,

I just switched off/removed the pages

- Forums (never used)
- Tracker (almost never used, spammed)
- Tasks (almost never used)
- Docs (not used)
- Surveys (not used)
- News (not used)
- Files

from the XML/SGML teams homepage just to make it look clearer.
If necessary, reverse my action or ask me to do this.

Cheers!