Screen reader help

Add a default language and charset,
Change logo from inline image to empty span with a background image
Irc Tips

Link to webchat with channel / channel & nick filled in, link using
irc:// protocol for clients which register as irc:// handlers.

(Not very user friendly? TODO: rephrase in simple English.)
Merge pull request #14 from r4dian/Screen-Reader-Helpers

Change layout to be easier to read using screen readers
Use relative path to logo
Merge pull request #15 from r4dian/IRC-Links

Improve access to IRC
Merge pull request #16 from oskarfransson/gh-pages

Add 404 error page
Add what GA is not
Add favicon