[FIX] event: translate templates into user language

When sending an email of the registration/confirmation, the context was lost and the tempate sticked in en_US.
With the patch, the template will use the current user's language.
[IMP] stock: display translated selection value in message

When a user tried to delete a done or canceled picking, the error messages used to display the key of the selection field ('done' or 'cancel') which was surprising in other languages than English. This patch takes the string value of the selection field, keeping the context to get the translated value (opw 613068)
[FIX] purchase: keep fallback behaviour that was removed at rev 8973217

If no valid invocie is found on the purchase order line, use the price and currency of the line (coherent with help message)
Forward port of 7.0 up to rev 9b87d6f
[FIX] correctly forward context in graph view

the new graph view silently ignored the context when doing its rpc
read_group.  Usually, it's not really a problem, which is why it is only
now being fixed, but some models actually use the context in read_group.
(for ex, account_entries_report)
[FIX] account_voucher: convertion rate of purchase receipt

The conversion of currencies in vouchers are made based on payment_rate_currency_id field (instead of usual currency_id).
This field was not present in the purchase view and not correctly set when we change the journal (and thus the currency) which was leading to rates of 1. With a rate of 1, the amount is equal to the currency amount (which is rarely correct). opw 611254
[FIX] auth_ldap: remove unused sql column
[FIX] account_voucher: import invoices, sign according to transaction type
[FIX] website_blog: portal users should not be able to read unpublished blog posts
[FIX] wms: fix lookup of xmlid route_warehouse0_buy

Fixes #2610 courtesy of gurneyalex
[FIX] l10n_be: Fix BS and P&L
[I18N] Update translations from Launchpad 8.0 branches

server: rev. 26 rev-id launchpad_translations_on_behalf_of_openerp-20140923072744-tkfs0yinu8msjh09
addons: rev. 39 rev-id launchpad_translations_on_behalf_of_openerp-20140923072715-5j7qvnuvmmb1zzy1
web: rev. 23 rev-id launchpad_translations_on_behalf_of_openerp-20140923072757-jvh9l6r2x0vfcyhb
[FIX] Report: compatibility issues on Windows

This commit fixes two different issues specific to Windows:
* NamedTemporaryFile behavior, requiring a file to be closed before being
  accessed a second time
* Wkhtmltopdf crash when the document's dpi is inferor to 96
[FIX] report: windows: lower level of file opening/closing, which to find wkhtmltpdf

* Use of 'which' to find the wkhtmltopdf binary (allow the win32 service to find it)
* Use of mkstemp and manual close of the file descriptors
[FIX] account: typo in conversion to new API
[FIX] Update README for 8.0
[FIX] widget html: rendering issue in mail composer on Firefox
The cleditor width does not include the margins. Setting 100% will make the editable area too large (104%) on Firefox (opw 611700).
This issue was already fixed in newer releases, from commit 9247c37de7d67beb479905e218656665dc12391f
Nevertheless, it introduced a new issue: while editing the form, the content of widgets html which were located in hidden notebook pages weren't displayed when displaying the page content.
opw-614448
[MERGE] forward port of branch 7.0 up to 9c77f79
[I18N] Update translation templates with latest term changes
[FIX] product: typo in field string