[IMP] [ADD] event: mail schedulign system.

This commit adds a way to configure scheduled emails on events. It replaces
existing automatic emails at confirmation and subscription. It proposes to
configure some schedulers, based on subscription or event, using a template
and a configurable timedelta.

A cron is added that regularly checks for event mailing schedulers to execute
and launch them. The granularity of send emails is therefore limited to the
granularity of the cron, aka 1 hour.

[TEST] Added tests for this feature.

Also cleaned a bit event, country_id is now a pure related instead
of a computed field trying to be a related. Also removed default templates
on event category. Configuration in the event itself should be easy
enough for most use cases.
[IMP] web client refactoring: action and view manager

large rewrite of action manager, view manager and
viewmanageraction.  The goal is to lay the foundation
for the redesign of the advanced search view.

This commit includes:
* improvements to the display order (no/less flickering)
* large simplification of the breadcrumbs code
* much better html layout for the header (no table)
* bootstrapisation of the view manager
* lots of optimizations/simplification
* a base.css.map, courtesy of the last sass version
[FIX] fixes many issues with the various views

the views don't always return a proper promise, or were
somewhat fragile and broke with the changes in the view
manager.
[IMP] readd pager functionality to web client

The pager was removed in the refactoring of view manager. This commit
readd the pager, and improves its rendering to avoid flickering
[IMP] graph view integration into view manager header
[IMP] rewrite of search view/view manager

Second part of a large refactoring.  Lots of cleanup, simpler code organization, and it should be faster.
[FIX] make add to dashboard work

With the search view refactoring, the add to dashboard functionality was unavailable.  Weep no longer, it is fixed.  The dashboard button is now an action in the favorites submenu instead of a search input
[FIX] readd the google spreadsheet functionality

It is now an item in the favorite submenu (search view)
[IMP] integrate mail client actions with search view

The mail client actions did not integrate with the search view.  (it is actually an ugly hack to fake a view manager and instantiate a search view. of course it was broken when the search view was refactored)
[FIX] a few bugs in view_form/view_list

some small stuff...
[IMP] add basic pivot support

The goal is to split the graph view into two views: pivot table view (short: 'pivot') and graph view (with charts).  This patch lays the foundation for that work.
[FIX] make the view editor work

with the recent changes in view manager, it was kind of broken.
[IMP] some cleanups in graph/kanban views

notable: disable the group by integration in graph view, because of crash (the search view was rewritten and too much search logic was in the graph view.  This is a temporary measure, the graph view will be split into pivot/graph views, and the search integration will be done correctly in the near future.
[IMP] various code cleanups

remove some old cruft
[FIX] update the search tests

The search tests are totally outdated since the search view rewrite. This commit update them to the new search view.
[FIX] catch possible exception in search.js

The search view tries to evaluate the category of a filter in order
to put it in the filters or in the group by sub menu.  The pyeval.eval
function could throw an exception, which is not cool if it crashes the
client.  This fix make sure that the exception is caught.
[FIX] update tests in search view
[FIX] remove search.invisible tests

The search view architecture allowed an 'invisible' attribute in fields.  These fields were ignored for the autocompletion and did not appear in the interface.  The goal was to allow default parameters to create facets, without displaying the field in the interface.  Since that functionality is not used and the new search view does not support it right now, the tests can be removed.
[FIX] put the scrollbar back in web/tests

for some reason, the web tests interface loads base.css, in which the .openerp is overflow:hidden, which is not fun in the tests.

The correct fix is actually to remove base.css from the tests, but the way I did it had some problems. So, this is a simple workaround that can be safely removed if base.css is removed from the view.
[FIX] fix a crash in sub kanban views

sub kanban views is sometimes initialized without a $buttons attribute in options.  In that case, it should just ignore it.