- global categories' options : instead of N horizontal tabs on a single

page, N options in the left menu (but the same backend)

- categories.global_rank : new calculated field. It gives a global rank of
  the category among all others (updated during ordering)

- category.php page : menu is generated faster thanks to
  categories.global_rank, recursivity becomes useless :-)

- new function to display select box with a set of categories :
  display_select_cat_wrapper

- cat_options : instead of using 1 multiselect for true/false items, using 1
  multiselect for true, and another one for false. The form provides buttons
  with arrows to switch categories from one multiselect to another

- deletion of obsolete function display_categories (working with the old
  template system)

- deletion of obsolete functions get_user_plain_structure,
  create_user_structure, get_user_subcat_ids, update_structure, count_images
  : useless thanks to global_rank


git-svn-id: http://piwigo.org/svn/trunk@614 68402e56-0260-453c-a942-63ccdbb3a9ee

install/dbscheme.txt

@@ -31,6 +31,7 @@ column:uploadable                table:categories     type:enum('true','false')
 column:representative_picture_id table:categories     type:mediumint                nullable:Y length:8   signed:N
 column:uppercats                 table:categories     type:varchar                  nullable:N length:255 binary:N
 column:commentable               table:categories     type:enum('true','false')     nullable:N
+column:global_rank               table:categories     type:varchar                  nullable:Y length:255 binary:N
 column:id                        table:comments       type:int                      nullable:N length:11  signed:N
 column:image_id                  table:comments       type:mediumint                nullable:N length:8   signed:N
 column:date                      table:comments       type:datetime                 nullable:N

install/phpwebgallery_structure.sql

@@ -25,6 +25,7 @@ CREATE TABLE phpwebgallery_categories (
   representative_picture_id mediumint(8) unsigned default NULL,
   uppercats varchar(255) NOT NULL default '',
   commentable enum('true','false') NOT NULL default 'true',
+  global_rank varchar(255) default NULL,
   PRIMARY KEY  (id),
   KEY categories_i2 (id_uppercat)
 ) TYPE=MyISAM;