This patch adds 2 columns in the aqorders table :
- claims_count : number of claims for an orders
- claimed_date : date of the lastest claim

In the lateorders.pl table, you can not select orders from different
supplier because there is just one letter sent after clicking the "Claim
order" button. So, it's logic that you want to select only orders from
this supplier.

Modification in C4/Letters.pm:
refactoring code for claimacquisition and claimissues letter type.
Now, fields for theses letters check the table name. It's not possible
to chooce aqorders.title, this field doesn't exist !
Furthermore, you can add a <order> tag around your item fields, like
this :

-- Begin example
<<LibrarianFirstname>>
<<LibrarianSurname>>

<<aqbooksellers.contact>>
<<aqbooksellers.address1>>
<<aqbooksellers.phone>>
<<aqbasket.basketno>>
<<aqbooksellers.phone>>
<order>Library : <<items.homebranch>>
In your possesssion : <<biblio.author>>. <<biblio.title>>.
<<biblioitems.publishercode>>, <<biblioitems.publicationyear>>.
Callnumber : <<items.itemcallnumber>>. doc type : <<items.itype>>
Barcode : <<items.barcode>>
Date for the return : <<items.onloan>>.</order>

<<LibrarianSurname>>
-- End example

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>