Implement extrafields : calendar on date type and new separator type
New method to CommonObject to display extrafields data output
Try for product
New option (MAIN_EXTRAFIELDS_USE_TWO_COLUMS) to split extrafields display into 2 columns
For thirdparty use new method to display extrafield values
Work on new menu managers - step x
Fix : in extrafield force output for date selector
Unique function to show input or output of extrafields datas
Use new function to show extrafields on products
Uniformize usage of extrafields methods
Merge branch 'develop' of git://github.com/Dolibarr/dolibarr.git into extrafields

Conflicts:
	htdocs/comm/propal.php
Another step for menu management rewriting
Merge pull request #792 from grandoc/develop

try to fix :supplier invoice numbering
Fix: Restore lost commit.
Merge pull request #793 from jfefe/extrafields

Task #784 : display calendar into data type extrafields / new methods to manage extrafields
Merge branch 'develop' of git@github.com:Dolibarr/dolibarr.git into develop
Fix: Default background if css3 not used
New: Add option INVOICE_CAN_NEVER_BE_REMOVED
New: Add option INVOICE_CAN_NEVER_BE_REMOVED