Add new ad on overview page for spreeconf
[preferences guide] added 1 sentence about where Spree::Config comes
from.
Merge pull request #88 from westonplatter/master

Added 1 sentence describing where Spree::Core comes from
Link to Deface's new home.
Merge pull request #91 from splattael/correct-deface-link

Link to Deface's new home.