[FIX] account: better error message when regenarating opening entries (opw 606923)

If we try to generate twice entries on the same fiscal year, we can get completly unrelated errors ("You can only reconcile journal items with the same partner").
With this, we make sure people will first cancel the entries before regeneraing the entries.
[FIX] point_of_sale: it was impossible to delete a pos session
[FIX] sale: only propose services for pay advances

When creating an invoice from a sale order, if the user choose to invoice a fixed price (deposit), he has the possibility to choose an advance product. As described in the help message, this product should be a service product. Therefore, we add a domain so only services are displayed in the dropdown list
[FIX] read() method returns None values incompatible with XML-RPC
[IMP] website_quote : remove press edit button on template
[FIX] hr_attendance: typo introduced at rev 1c9e8ba077b296ec9c334800915fbbf76c81310c
[FIX] project : do not show canceled projects in task

fixes #938, opw 610318
Merge branch 'master' into master-pos-small-imps-of-july-fva
[FIX] web: reload after wizard when record has been removed cause exception

If an action unlink the current records (e.g. unreconcile on account.move.reconcile), trigger history_back to avoid errors when trying to reload inexistant record (opw 607883)
This is a partial backport of saas-4 code (rev c0db6ae, 162ad1c) and should not be forward ported.
[MERGE] forward port of branch 7.0 up to 680f955
[IMP] point_of_sale: show traceback popup when there is a server error when posting orders (which should NEVER happen !)
[IMP] point_of_sale: add debug popup that displays unsent order data, for when localStorage is hard to inspect
[IMP] point_of_sale: add a debug option to delete all unsent orders
[FIX] delivery: use unit of measure and not unit of stock to compute price of delivery

The computation expects uom and it was wrongly passing uos qunatities.
[FIX] website_sale_delivery: avoid selecting unavailable delivery method

If somebody selects a delivery method not matching any criteria, the server would crash (500 for the user). This is due to error raised in get_price_from_picking which is triggered by the function field 'price' on the 'delivery.carrier' object.
To avoid this, add field 'available' on the carrier that will be False when no delivery gird is found or when the error is raised. In this case, the delivery choice is disabled. opw 610210
[IMP] sale_stock Show the button 'view delivery order' as soon as a picking exists

The button should appear no matter the state of the sale order, to be consistent with the rest of the application.
This makes it much faster for the sales person to find out about orders in shipping exceptions or already processed.
Fixes #256
[FIX] sale, crm_claim, crm_helpdesk: report menus

crm claims and helpdesk reports should be in Sales Report menu, not in project
The sales report menu is now defined in sales_team, which is a common dependance between crm and sales, instead of redefining this menu in each modules
[FIX] account: using wizard methods instead of invoice methods

Typo during port of account.invoice to new API.

(Rebase of 02a36b6 for #1052)
[FIX] website_sale: _rec_name product.attribute.line

Set the _rec_name for product.attribute.line model, as its column name wasn't defined, and therefore search on it wasn't possible (For instance, do an advanced search on product.product with "Product Attributes" "Contains" "Something" wasn't possible).
[FIX] stock: wrong target table and function for lot_ids in stock.move