Bugfix: make extension_url contain correct url in all cases

The old code populated _extension_url with contents like
https://example.org/var/www/sites/htdocs/wp-content/plugins/redux-framework/
-> ReduxCore/inc/extensions/customizer/

New implementation is does not mind if Redux is embedded in a theme or plugin,
supports having WordPress installed in any directory and to avoid future bugs:
the new code is clean and easy to read.

Author: ottok

extensions/customizer/extension_customizer.php

@@ -80,7 +80,8 @@ public function __construct( $parent ) {
         add_action( 'customize_save_after', array( &$this, 'customizer_save_after' ) ); // After save
         if ( empty( $this->extension_dir ) ) {
           $this->extension_dir = trailingslashit( str_replace( '\\', '/', dirname( __FILE__ ) ) );
-          $this->extension_url = site_url( str_replace( trailingslashit( str_replace( '\\', '/', ABSPATH ) ), '', $this->extension_dir ) );
+          preg_match("/wp-content\/(.*)/", $this->extension_dir, $match);
+          $this->extension_url = site_url('/wp-content/'.$match[1]);
         }
 
       }

extensions/edd/extension_edd.php

@@ -52,9 +52,10 @@ public function __construct( $parent ) {
 
         if ( empty( $this->extension_dir ) ) {
           $this->extension_dir = trailingslashit( str_replace( '\\', '/', dirname( __FILE__ ) ) );
-          $this->extension_url = site_url( str_replace( trailingslashit( str_replace( '\\', '/', ABSPATH ) ), '', $this->extension_dir ) );
+          preg_match("/wp-content\/(.*)/", $this->extension_dir, $match);
+          $this->extension_url = site_url('/wp-content/'.$match[1]);
         }
-        
+
 
         if ( isset( $parent->args['edd'] ) && !empty( $parent->args['edd'] ) ) {
           // Create defaults array