Add help about extrafields in ODT propal
Fix : incorrect function used to retrieve extrafields for propal
Add param to define key name in return array of substitution function
for propal
Fix : change to variable with unused name
Add information about linked proposal into basic ODT template for invoice
Merge branch 'extra_propal' into fgd

Conflicts:
	htdocs/core/class/commondocgenerator.class.php