[FIX] web: webclient_bootstrap: render the menus when the user is really a user

The webclient rendering is done in two parts: the server renders the boilerplates
including the menus, and then the  javascript launch the webclient using the
server-side boilerplates. In some case, we want to render the boilerplates but not
the menus (auth_calendar). Added groups around the t-call to the menu in the web
template. Fixes issue #2044.
[FIX] Calendar: fix some display issues

* render the invitation widget inside oe_application
* override the margin of oe_right in order to display the two div on the same line
Merge branch '8.0' of https://github.com/odoo/odoo into 8.0-linux64