anchor popup attribute missing

Please add the menubar attribute to anchor popup
Fix #3161
Fix #3160
Update url_helper.php
Support for menubar attribute to the :func:`anchor_popup()` 

Now the menubar can be set to yes with anchor_popup() by adding new attribute array element 'menubar' => 'yes' 
The list of all available attribute for anchor_popup() function will be 
$atts = array('width' => '800', 'height' => '600', 'scrollbars' => 'yes', 'menubar' => 'no', 'status' => 'yes', 'resizable' => 'yes', 'screenx' => '0', 'screeny' => '0');
Update url_helper.php
Update url_helper.php
Last empty line remove
Merge pull request #3162 from MianSaleem/patch-1

anchor popup's menubar attribute is missing
Make CI_Pagination properties per_page, cur_page public

Useful if you want to make calculations based on them.