FriendFeed module does not generate valid XHTML

Issue Summary

The FriendFeed module does not currently generate valid XHTML. I changed it so that the ALT text is empty (I considered putting in the service name, but the same text link is already available below for each item) and set the style of the icon in a separate stylesheet. I also extracted the font size setting from the html to the stylesheet for the source line.

I also removed the left alignment of the service icon since I wasn't sure what it was for and didn't want to worry about right-to-left stylesheets. It seems to be look OK in both Safari and Firefox.

I've attached the patch containing the changes.