Fix first day of the week in datepickers

Fixes #2188
Appointment editor: fix until date timezone

.. and untabify the file!
iCalDateTIme: fix all-day entities

When setting an all-day entity (no time), make sure to set the
NSCalendarDate to GMT before formatting the string.
Fix recurrence-id of all-day events

Recurrence-ID of all-day events must be defined as a date (VALUE=DATE).
Fix exceptions of recurring all-day events
Update documentation and NEWS file
rhel: create the sogo user as a system user

Fixes #1470
Merge remote-tracking branch 'origin/master'

y this merge is necessary,
spec: sogo user as a system user, perms fixes

Create the sogo user as a system user
Use %attr() to set directory permissions instead of chown/chmod
Use more restrictive permissions for the log and spool directories
Improve JS regexp for email addresses
Fix localization of recurrence editor
Update German translation
whitespace (tabkill)
whitespace (tabkill)
Rewrite useradd for debian packages

Add the sogo user as a system user
Create and/or fix the permissions/ownership of various directories when
installing or upgrading the package.
Use 'sogo' group instead of 'adm' in init script

This matches what the package preinst script does.
test-sogo-tool.py: Use sudo instead of su -
NEWS: Add note related to sudo -u sogo usage
Plug ldap fd leak in login checks
Add note about 'requiretty' in sudoers file