[IMP] product: name_get matching on commercial_partner_id for suppliers

The name_get of a product will use some information (e.g. default_code) based on the supplier.
The matching of the supplier should use the commercial_partner_id in case the supplier info are on the company and the partner_id in the context belongs to the company (e.g. creates quotation with a contact of the company).
Fixes #1219
[FIX] account_analytic_analysis: invoiced field takes customer invoices only

Besides, it subtracts customer invoices with customer refund invoices
[FIX] auth_oauth: fb and google oauth providers reset on general settings apply

 - The res_config.xml file was missing in the manifest (so couldn't check the use of FB and Google OAuth from the general settings)
 - The default value for these oauth configuration were not set
[FIX] ir_attachment: restrict access to orphan attachments to employees
[FIX] account: return format of function field

When no result is found on the function field 'invoice' (account.move.line), instead of returning {move_id: (False, '')}, return {move_id: False} (expected for m2o fields)
Fixes #2138, opw 613096
[FIX] ir_translation: remove control characters from translations

This is possible that control characters (such as line returns) are inserted wrongly in translations
These should not influence on the web interface
[FIX] ir_translation: apply tools.ustr on the trad itself

tools.ustr(None) returns u'None', res[0] can be None.
[FIX] point_of_sale: do not display False as currency if symbol is not set
[FIX] account_anglo_saxon: price difference, discount and taxes

When computing the price difference amount do not integrate the eventual discount and taxes included in the price.
Otherwise the total of the generated accounting enty would be higher than the total of the invoice. opw 611350
[FIX] event: missing context

This fixes some translation issues (templates not translated at event confirmation)
[FIX] event: double context