Conflicts:
	htdocs/projet/fiche.php

Change-Id: I7607f97d21cc695c9b295d94f5abcb64fe25f3af

Holidays module improvements

Update project.class.php

Update projects.lang

Update element.php

Conflicts:
	htdocs/holiday/fiche.php

Translations made by Juanjo Menent (simnandez)

Add feature to add element in elements page of a project

add feature: join element from element page

Add Link element on elements page

Fix: [bug #856] Mail error if destination user doesn't have an email

Conflicts:
	htdocs/comm/propal/class/propal.class.php
	htdocs/compta/facture.php
	htdocs/compta/facture/impayees.php
	htdocs/compta/index.php
	htdocs/core/boxes/box_produits_alerte_stock.php
	htdocs/core/class/html.form.class.php
	htdocs/core/modules/syslog/mod_syslog_file.php
	htdocs/fourn/facture/impayees.php
	htdocs/holiday/class/holiday.class.php
	htdocs/holiday/fiche.php

Fix : use standard method to show extrafields on propal

Holidays translations