Remove references to severely outdated plugins.

The Platinum SEO and Comment-lisence plugins are no longer maintained. Reference to them should be removed (Platinum SEO should perhaps be depreciated in the theme as well).
Wrap siteinfo in a paragraph tag.
Avoid margin on siteinfo div due to added paragraph tag.
Remove references to the old ThemeShaper forums and google code.
Merge pull request #37 from SeamlessThemes/develop

Update readme references to Thematictheme site and github
Wrap siteinfo in paragaraph tags
Remove references to outdated plugins in readme file