[ui:dialog] fix #2551 trigger dialogopen event before open the dialog

Example: Make the edit dialog the same size as the elFinder node

To define with `handlers.dialogopen: [Fn]` of the client setting or `elFinderInstance.bind('dialogopen', [Fn])`.

```javascript
handlers : {
    dialogopen : function(e, fm) {
        var dialog = e.data.dialog,
            elfNode;
        if (dialog.hasClass('elfinder-dialog-edit')) {
            elfNode = fm.getUI();
            dialog.css({
                top: 0,
                left: 0,
                width: elfNode.width(),
                height: elfNode.height()
            }).trigger('resize', { init : true });
        }
    }
}
```

js/ui/dialog.js

@@ -54,8 +54,9 @@ $.fn.elfinderdialog = function(opts, fm) {
 		if ((dialog = this.closest('.ui-dialog')).length) {
 			if (opts === 'open') {
 				if (dialog.css('display') === 'none') {
-					dialog.trigger('posinit').fadeIn(120, function() {
-						dialog.trigger('open');
+					// Need dialog.show() and hide() to detect elements size in open() callbacks
+					dialog.trigger('posinit').show().trigger('open').hide();
+					dialog.fadeIn(120, function() {
 						fm.trigger('dialogopened', {dialog: dialog});
 					});
 				}
@@ -353,8 +354,6 @@ $.fn.elfinderdialog = function(opts, fm) {
 					});
 				})
 				.on('open', function() {
-					var d = $(this);
-
 					if (syncSize.enabled) {
 						if (opts.height && opts.height !== 'auto') {
 							dialog.trigger('resize', {init: true});
@@ -393,6 +392,8 @@ $.fn.elfinderdialog = function(opts, fm) {
 
 					dialog.trigger('totop');
 
+					fm.trigger('dialogopen', {dialog: dialog});
+
 					typeof(opts.open) == 'function' && $.proxy(opts.open, self[0])();
 
 					if (opts.closeOnEscape) {
@@ -687,7 +688,7 @@ $.fn.elfinderdialog = function(opts, fm) {
 			overflow   : dialog.css('overflow')
 		};
 
-		dialog.trigger('posinit').data('margin-y', self.outerHeight(true) - self.height());
+		dialog.data('margin-y', self.outerHeight(true) - self.height());
 
 		if (opts.resizable) {
 			dialog.resizable({
@@ -714,12 +715,12 @@ $.fn.elfinderdialog = function(opts, fm) {
 			}).data('hasResizable', true);
 		} 
 
-		typeof(opts.create) == 'function' && $.proxy(opts.create, this)();
-
 		numberToTel();
 
 		tabstopsInit();
 
+		typeof(opts.create) == 'function' && $.proxy(opts.create, this)();
+
 		opts.autoOpen && self.elfinderdialog('open');
 
 	});