Add feature to add element in elements page of a project

add feature: join element from element page

http://wiki.dolibarr.org/index.php/Extrafields

Fixes project cloning

Look: Optimize for smartphone

rename search_product by search_project (the real search thing)

Uniformize propal code (not use addpropal.php)

can move it during init of environment and use it globally.

upgrade were not yet received. So we prepare for GPL by uniformizing
licence text keys to GPL-3+. Will move later to AGPL if all answers are
positive.

Conflicts:
	htdocs/projet/class/project.class.php