MDL-36607: Improve block drag and drop

* Adding support for subpage
* Adding support for regions that do not start with "side-"

lib/yui/blocks/blocks.js

@@ -99,7 +99,13 @@ YUI.add('moodle-core-blocks', function(Y) {
         },
 
         get_block_region : function(node) {
-            return node.ancestor('div.'+CSS.BLOCKREGION).get('id').replace(/region/i, 'side');
+            var region = node.ancestor('div.'+CSS.BLOCKREGION).get('id').replace(/region-/i, '');
+            if (Y.Array.indexOf(this.get('regions'), region) === -1) {
+                // Must be standard side-X
+                return 'side-' + region;
+            }
+            // Perhaps custom region
+            return region;
         },
 
         get_region_id : function(node) {
@@ -207,6 +213,7 @@ YUI.add('moodle-core-blocks', function(Y) {
                 courseid : this.get('courseid'),
                 pagelayout : this.get('pagelayout'),
                 pagetype : this.get('pagetype'),
+                subpage : this.get('subpage'),
                 action : 'move',
                 bui_moveid : this.get_block_id(dragnode),
                 bui_newregion : this.get_block_region(dropnode)
@@ -262,6 +269,9 @@ YUI.add('moodle-core-blocks', function(Y) {
             pagetype : {
                 value : null
             },
+            subpage : {
+                value : null
+            },
             regions : {
                 value : null
             }