[IMP] doc/howtos/backend: improve exercises on relational fields
[FIX] Survey: typo (en_US wording)
[FIX] website_forum: fixed comment unlink action :
- fixed call to a wrong method
- fixed button display, now based on the standard way of managing karma (popup when
not having the required karma)
- fixed button display karma computation
- some css tweaking for this button
[FIX] website_event: pager now takes into account the searches performed
by the user. Otherwise it was resetting the search to all events.
[FIX] res_partner: Meetings button on form view was not correctly
filtering displayed meetings according to the selected partner.
[FIX] language and model converter redirections should use code=301
[FIX] stock: moves link on product form opening wrong view

Fixes #2008
[IMP] doc/howtos/backend: add section on wizards
[FIX] portal_sale: portals are not allowed to see payments

Portal users are not allowed to read account.move.line model
Therefore, in the portal, if you let the payments in the invoice view, the portal user is warned that he is not allowed to see account.move.line
[IMP] Increase statics cache from 12 hours to 1 week
[IMP] website_forum_doc: add clickable on tree view of forum.post and add default stage to create forum post.