[FIX] add missing claim_count field to stock.picking.out

The claim_count field was incorrectly added into addon stock instead 
of addon claim_from_delivery.  The commit adding the claim_count field
in stock.py was reverted, but claim_count is still needed in 
claim_delivery_view.xml.
[IMP] change claim_count in claim_count_out (addon claim_from_delivery)

also, simplify the implementation.  The empty method _claim_count in
stock_picking_out is due to the weird way inheritance works in openerp,
and the fact that stock.picking.out only call the method in its parent
[IMP] change the method name _claim_count into _claim_count_out

also, add a comment to explain why it is necessary to add a _claim_count_out method in 
stock_picking_out even though it will not be called.
[MERGE] merge trunk-claimcount-fix-ged

Add the claim_count_out field to its correct place (in addon claim_from_delivery).  The field was removed because it was incorrectly added to stock.py instead of the addon claim_from_delivery.  (note: it was renamed from claim_count to claim_count_out)