Although it should never happen in normal use, it may happen during an
upgrade when property sheets fail creating accessors (ex: broken object
because portal type moved to a different Business Template).

Also, avoid reindexing when object is not modified.

This also fixes the problem that in recent pytz common_timezones is a LazyList that does not work in restricted python

make FTPConnector.getFile binary mode by default, because ascii mode only works with utf-8 encoding.

also propagate binary mode to SFTPClient.file().

Reverse natural ways, has suggested by the document (presentation) with
reference developer-Calendar

This is useful to get both start and stop dates of movements without the need of
getting directly objects.

All the logic was inside Person_getAvailableTimeMovementList.
Algorithm was old and hard to understand. Move this algorithm to
simulation tool, and rewrite it using the interval library for
having less code to maintain and easier understanding

This makes less code to customize in GroupCalendarAssignment

Calendar Assignments are now handled in a separate module, update
code in consequence

Not only returns start and stop dates, but also quantity defined
on presence periods. This make it possible to set 3 hours availability
in a time range of 10 hours.

When a Group Calendar or a Group Presence Period is updated, it's necessary
to update related Group Assignment stock catalog data since values are dependent.

This allows to define specific security setting and workflow for Group Calendar Assignments. Before
they were inside Group Calendars. Now a Group Calendar Assignment use the specialise Base
Category to specify the corresponding Group Calendar.

Improve sql query to consider only accountable lines and get the avaibility with many nodes in the same query

Move changes on asMovementList method from PresencePeriod to GroupCalendarAssignment to keep Leave Period working as Expected.

This reverts commit cbf5d46e3c1d3e76c6a5376e08617851ce03773c.

remove the calendar base category on Assignment portal type because the relation between Assignment and Group Calendar is obsolete

Add Group Calendar Assignment portal type. It will be used to set the relation with the source and the period

otherwise pylint-1.2.0 seems not working.