-Titlecase terms, uppercase abbreviations, avoid jargons, add titles to empty title forms....

* it is faster.
* it does not require Products.

Allow client side to specify how it want server to return listbox field - i.e. it can be rendered locally or rendered entirely server side.

Fixes copy-paste of DateTimeField rendering into search expression, as it
separates time from date with 3 spaces.

Original code behaviour:
>>> def foo(self, a=None):
...    return 'works'
...
>>> context.foo(a=1)
works
>>> def foo(self, a):
...   return 'works'
...
>>> context.foo(1)
works
>>> context.foo(a=1)
TypeError: foo() takes exactly 2 non-keyword arguments (0 given)

New behaviour fixes this TypeError, to be closer to normal python
behaviour.
Also, original code was doing expensive checks before cheap ones.

Also, use from ... import * to make verbatim original code work.
Also, use original code's coding style for unaltered lines.

For easier copy/paste from original file.

Implement properly portal status message gadget to be a global one and support showing message from URL.
Implement properly DateTimeField.

This avoid having some failures of testnodes

Return listbox's as rendered at server side (until we can render it client side with all features).
When tab changes preserve URL arguments in browser location bar and change only hash part.
Make basics of RelationStringField.
Improve rendering of ERP5 form's left and right fieldsets.