The pyeval name is quite confusing, given that there is already an eval
and an evaluate function in py.js, and that the web.pyeval exports two
evaluate functions.

Since this file is more about odoo specific customization to py.js, it
is renamed in py_utils to better express its intended use.

When evaluating a context, we need to use the server format for dates,
because the context will ultimately be sent do the server.  Also, moment
objects are not known by pyeval, so they simply cause a crash (for
example, see bank statements form view, edit it, click on 'add an item')

With this commit, we make sure that the evaluation context is correct,
with respect to dates (we use the toJSON method, because that is the way
we get the server compatible date)

This commit tries to refactore the management of contexts and domains
in the webclient.

- Get rid of CompoundDomain: use standard array manipulation to
join multiple domains or use the Domain class (to be improved)
- Get rid of data.js build_domain and build_context methods
- Link this.record to the data point from the basic model for all
fields (not only relational fields)
- Add a getContext and a getDomain function to the basic model
data point (localData element) so that AbstractField implementations
can use them thanks to their this.record element.
- Remove the autocontext binding for field RPCs (see FieldManagerMixin)

We want to remove data.js, but we still need the CompoundContext class,
so we take it out, and rename it 'Context'