Before this change, expression_instance would not be set when expression is
modified, leading to either non-applied filter expression (when no
expression_instance existed) or use of an outdated expression.
Use a volatile attribute to store the expression: it does not change the
amount of work needed to load the Expression instance (pickle is the raw
python expression as text) and it remove data duplication in exported
documents.

This reverts commit fe84b799.
I did not intend to push that hash (copy/paste mistake).

monospace, sans-serif, serif, OpenSans

[hal_json] Improve backward compatibility of value resolution by calling Scripts on search result underlying object

This adds the maximize button.

This reverts commit c49cf8d8.
Callee is directly accessed from other places, so changing this API is
wrong.
This it not immediately visible in tests, but this makes
erp5_officejs_support_request_ui_test:testFunctionalSupportRequest
testCheckComment test randomly fail (apparently because the javascript
error message may appear after or before the test final step is
satisfied - which means this tests is bugged, but that's a separate
issue).

These variables are only used when they evaluate as true, so it is
pointless work to replace them with empty lists.

Catalog used in this test is now close/above 1k rows, so go one API level
down to get control over that pesky "limit 1000".

These tests do not test what they advertise anymore. Advertised features
are in widespread use in other tests, so there should be no need to test
specifically for these.
Also, avoids polluting other tests by clearing catalog for futile reasons.

ZSQLCatalog/ERP5Catalog is only supposed to work on catalog table, by
definition.

Also, reorder imports to follow python style: standard modules before
others.

Current scheme causes paths to exceed catalog limit.