fixed guard for cv::text methods, which are not available in 3.0.0
fixed guard for cv::text methods, which are not available in 3.0.0

justadudewhohacks/opencv4nodejs,justadudewhohacks/opencv4nodejs,justadudewhohacks/opencv4nodejs,justadudewhohacks/opencv4nodejs,justadudewhohacks/opencv4nodejs,justadudewhohacks/opencv4nodejs