[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]Improved language feature:Added button in tree of language to active/deactive,Added alertbox in all for translation,deactive english lang when db create with anyother lang,Added constraint when try deactive prefferd language,

[IMP]Improved feature:1.when deactive base lang:seted last loaded language in base lang,seted base lang on partner and user,loaded translation which language is active or inactive,2.seted active true when try to load language and when it is deactive.

[IMP]Added disable/enable button in form view of language same as publish/unpublish, for that added widget,template,css class.

[IMP]Added language.sass file,passed contex in some method.

[IMP]Moved enabled/disabled button on top right of language form view.

[IMP]Removed code to write lang on load of new language,in translation message set name instead of code.

[IMP]move code from set_status to write method,used baselang to writein all partner.

[IMP]Improved code to translate other language to en_us language.

[REM]Removed record for english lang from base data file and removed code for deactive this language.

[IMP]Removed search for en_US from domain.

[IMP]Improved code for fixed traceback

[REV]Revert all changes for remove english language.

[IMP]Improved code to do not translate when single lang is enable

[ADD]Added def fields_get in ir.translation to change label of field source when en_US is active otherwise keep as it.

[IMP]Improve code to display icon and to translate.