[FIX] web_tip: handles `content changed` event in forms; minor fixes

* eval tip on form content changes
* prevent multiple tip trigerring in some cases
* use scrollTo jquery plugin
[ADD] website: new blog demo snippets

(cherry picked from commit 6c6df546eb5a99d00d62fc6b497b4b861431423e)
(closes #2631)
[IMP] base_action_rule: allow using the CharDomain widget
to set the filter and pre-update filter. Using ir.filters is still
possible, but is not the only way anymore of setting the domains
used in the base action rules.
[IMP] crm, project, hr_recruitment: star (priority) management: less possible values, too much stars are too much tears !
[IMP] account: remove inexistant sequence get

There is no sequence for account.bank.statement.line to prefill the field name (Communication), better remove it.
[IMP] website_forum : Karma check for tag creation and follow tag mechanism