Fixing various typos, also added a blurb about portage set support
Various fixes

- Update kernel numbering
- Use KDE 4.9 as example release
- Add online social communities
- Mention that /dev now is also kernel-provided (well, optionally)
- Use /etc/portage for make.conf
- Drop section on HAL (and automounting with it)
- Drop screenshots of graphical environments (outdated)