[0.85] prepare for #4330


git-svn-id: https://forge.indepnet.net/svn/glpi/branches/0.85-work@21585 35612d4c-9d10-0410-837c-bf9dd1be60d7
[0.85] Add a new column in Document tab showing in ticket see #4330


git-svn-id: https://forge.indepnet.net/svn/glpi/branches/0.85-work@21587 35612d4c-9d10-0410-837c-bf9dd1be60d7
[0.85] Sort linked documents see #1312


git-svn-id: https://forge.indepnet.net/svn/glpi/branches/0.85-work@21589 35612d4c-9d10-0410-837c-bf9dd1be60d7