[rb] put back the script method that was inadvertently deleted

Author: titusfortner

rb/lib/selenium/webdriver/common/driver.rb

@@ -99,6 +99,15 @@ def navigate
         @navigate ||= WebDriver::Navigation.new(bridge)
       end
 
+      #
+      # @return [Script]
+      # @see Script
+      #
+
+      def script
+        @script ||= WebDriver::Script.new(bridge)
+      end
+
       #
       # @return [TargetLocator]
       # @see TargetLocator