Even though we can have different transactions between the beginning and the
end of a test, transaction.get().__hash__() might return the same value. So
always resubscribe portal_activities if it was subscribed at the beginning

Changing 'datetime' to render µs can break existing code if the column has
lower precision. For example:

> insert into t values('2015-05-26 12:18:37'); select * from t where x='2015-05-26 12:18:37';
Query OK, 1 row affected (0.00 sec)

+---------------------+
| x                   |
+---------------------+
| 2015-05-26 12:18:37 |
+---------------------+
1 row in set (0.00 sec)

> insert into t values('2015-05-26 12:18:37.2'); select * from t where x='2015-05-26 12:18:37.2';
Query OK, 1 row affected (0.00 sec)

Empty set (0.00 sec)

Another example is when searching for stricly older documents than another one.
The latter could be wrongly included in the results.

Commit e0388ecc
("catalog: render µs in SQL methods") was also incomplete:
there's still no µs support in ZSQLCatalog.

that will raise an exception with Python 2.7.10.

This panel will get dynamic content depending of the element which requested it to be opened (like listbox domain tree, relation field, or whatever).

Global erp5 search should be a full page search (like in a module)

Add support to property array in erp5storage (like listbox_uid:list)

This is too inconvenient when resizing browser size, it requires in
some cases to do taller or shorter many times only because we resized
the browser

For Python3 compatibility, IPython introduced IPython.utils.ulinecache thus
update ipdb-specific monkey patch accordingly.