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 clicking on an element in a listview editable, the record_id
is not updated in the dataset, which means that when you switch to form
view, the list view does not display the last selected record.

Also, it should fix the issue solved by PR pull/2725

when the user press tab in editable list views, the focus is supposed to
go to the next cell unless it is at the last cell of the line.  in that
case, it is supposed to create a new record.

Sadly, when the last cell is readonly, this does not work.  This commit
make sure that read only fields are properly ignored when computing the
last_field state.

ignore .po and .pot changes

when the user press tab in editable list views, the focus is supposed to
go to the next cell unless it is at the last cell of the line.  in that
case, it is supposed to create a new record.

Sadly, when the last cell is readonly, this does not work.  This commit
make sure that read only fields are properly ignored when computing the
last_field state.