[FIX] point_of_sale: printing of tax name on hardware was missing data 'name', also made the regular print use the same value for consistency.
Merge pull request #3001 from Bubbles-IT/8.0-fix-pos-tax-label

[FIX] point_of_sale: printing of tax name on hardware was missing name
[FIX] models: do not look up the registry class when building cls._fields
[FIX] implementation of t-call's 0-index in qweb-js

Had expected regularity, had not noticed the Python version is really an
ignoble hack where the string "0" (exactly) is interpreted in a specific
manner when used in t-raw and format strings, *and nowhere else*.

Had special-cased the expression everywhere which broke e.g.
<t-set="xxx" t-value="0"/>. Reproduce Python behavior more closely,
and strongly consider swapping out both for something different e.g.
[[content]] or something like that, which doesn't cause problems in
Python but doesn't have to be so specially cased either.
[FIX] website: editor: preserve label and color for link buttons targeting a page

When selecting a page target rather than a static
URL the style and label information were ignored/lost.
[FIX] web: push render value deferred only if the field is in a form view
[FIX] mail_thread: allow to pass mail_track_log_only in the context to remove the subtype of the notification. By this way, no mails will be sent because partners_to_notify will be empty.
Merge branch '8.0' of https://github.com/odoo/odoo into 8.0-linux64