#3 Type in window_handles

[Alan Grunwald]

I've come across another typo, in the window_handles method in webdriver.tcl.

The method is currently defined as:

    method window_handles {} {
        # Returns the handles of all windows within the current session.
        # 
        # :Usage:
        #   driver window_handles

        return [my execute_and_get_value  $Command(GET_WINDOW_HANDLESS)]
    }

The index into the Command array should be GET_WINDOW_HANDLES.