add allotment and functional field in product rate to get rooms occupation
fix _get_occupation method, you can't acces suppinfo_id from product.rate
add module to merge travel products
change in allotment implementation
change to tabs in pricelist product views,  including button to print voucher from order line
add feature to export prices for customers
create interface to show allotments state for hotels and suppliers
do not create or delete allotment
order pricelists by date