Makes the cloud surface bigger. Maintains all word positions.

def expand(self,delta_width,delta_height):
        '''Makes the cloud surface bigger. Maintains all word positions.'''
        temp_surface = pygame.Surface((self.width + delta_width,self.height + delta_height))
        (self.width,self.height) = (self.width + delta_width, self.height + delta_height)
        temp_surface.blit(self.cloud,(0,0))
        self.cloud = temp_surface