[+] BO : Override of list, form or view fields

This is a method to allow to add fields in admin controllers.

in adminController.php, i add new functions to override in AdminController--- : 

getTemplateListVars()
getTemplateViewVars()
getTemplateFormVars()

Now i can easily add some new fields.

Sample:
In Override/.../adminControllerCustomer, i override these functions:

public function getTemplateViewVars()
{
     $myVars = array(..........);
     return array_merge($myVars, $this->tpl_view_vars);
}
Merge branch 'patch-20' of https://github.com/ccauw/PrestaShop-1 into ccauw-patch-20

Conflicts:
	classes/controller/AdminController.php
Merge branch 'ccauw-patch-20' into 1.6