GS/S Seaside site updated with latest manuals

I just changed the documentation links in the sidebar on http://seaside.gemstone.com/ from GS/S 2.4 to GS/S 3.0.1

All the GS/S 2.4 docs are still available under "GS/S 2.4 Documentation".

Last but certainly not least, I added links to the Smalltalk Industry Conference '12 at the Beau Rivage Resort and Casino in Biloxi, Mississippi -- March 18-21, 2012. Hope we see you there!

-- Monty