This commit introduces a new module system for the javascript code.
Instead of using global (namespaced) variables everywhere (like
openerp.web.whatever, ...), each file declare one (or more) module
with its dependencies.  Each module will be loaded after its
dependencies, and will be given a reference to the return values.

This change is a massive departure from the way the client worked
previously.  It will sadly break some/most history, but I am sure that
the future git ecosystem will allow you to easily browse the history
past this revision (one can dream).

This commit feature:
* main namespace is now odoo instead of openerp
* a way to define modules and dependencies (inspired by requirejs)
* many files have been splitted in simpler subfiles
* basic support for debugging in odoo.__DEBUG__
* no global variable (i.e. nothing in window.openerp)
* many bug fixes, many new bugs

Future vision: this modularization should simplify future code
development, simplify debugging and will allow a serious testing effort

When having several databases in the login form (not monodb mode),
when switching from one database to another,
if the company logo was different,
the company logo could be the logo of the database you came from.

fixes #5291
opw-628131

During the refactoring of the web client, the self.$el has been changed
from .openerp to body, so the notification was no more into the .openerp container.
Custom css (eg .highlight) was no more applicated.

Debian does not allow fetching data from external website at runtime.
This fixes the privacy-breach-generic lintian warnings for Debian packaging.
The removed youtube url was a dead link...