For review: Dynamic finders should go through AR::Base::find

Hi,

I have created a patch which makes the dynamic finder methods use AR::Base::find with :first, :last, and :all instead of :find_initial, :find_last, and :find_all.
This is because atm when one overloads ::find it doesn't apply to queries performed by dynamic finders.
Associations, for instance, do go through ::find, so this keeps it more consistent.

http://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/1162-dynamic-finders-should-go-through-arbasefind

Cheers,
Eloy Duran