feat: 切换后端至PaddleOCR-NCNN，切换工程为CMake

1.项目后端整体迁移至PaddleOCR-NCNN算法，已通过基本的兼容性测试
2.工程改为使用CMake组织，后续为了更好地兼容第三方库，不再提供QMake工程
3.重整权利声明文件，重整代码工程，确保最小化侵权风险

Log: 切换后端至PaddleOCR-NCNN，切换工程为CMake
Change-Id: I4d5d2c5d37505a4a24b389b1a4c5d12f17bfa38c

3rdparty/opencv-4.5.4/samples/python/contours.py

@@ -0,0 +1,74 @@
+#!/usr/bin/env python
+
+'''
+This program illustrates the use of findContours and drawContours.
+The original image is put up along with the image of drawn contours.
+
+Usage:
+    contours.py
+A trackbar is put up which controls the contour level from -3 to 3
+'''
+
+# Python 2/3 compatibility
+from __future__ import print_function
+import sys
+PY3 = sys.version_info[0] == 3
+
+if PY3:
+    xrange = range
+
+import numpy as np
+import cv2 as cv
+
+def make_image():
+    img = np.zeros((500, 500), np.uint8)
+    black, white = 0, 255
+    for i in xrange(6):
+        dx = int((i%2)*250 - 30)
+        dy = int((i/2.)*150)
+
+        if i == 0:
+            for j in xrange(11):
+                angle = (j+5)*np.pi/21
+                c, s = np.cos(angle), np.sin(angle)
+                x1, y1 = np.int32([dx+100+j*10-80*c, dy+100-90*s])
+                x2, y2 = np.int32([dx+100+j*10-30*c, dy+100-30*s])
+                cv.line(img, (x1, y1), (x2, y2), white)
+
+        cv.ellipse( img, (dx+150, dy+100), (100,70), 0, 0, 360, white, -1 )
+        cv.ellipse( img, (dx+115, dy+70), (30,20), 0, 0, 360, black, -1 )
+        cv.ellipse( img, (dx+185, dy+70), (30,20), 0, 0, 360, black, -1 )
+        cv.ellipse( img, (dx+115, dy+70), (15,15), 0, 0, 360, white, -1 )
+        cv.ellipse( img, (dx+185, dy+70), (15,15), 0, 0, 360, white, -1 )
+        cv.ellipse( img, (dx+115, dy+70), (5,5), 0, 0, 360, black, -1 )
+        cv.ellipse( img, (dx+185, dy+70), (5,5), 0, 0, 360, black, -1 )
+        cv.ellipse( img, (dx+150, dy+100), (10,5), 0, 0, 360, black, -1 )
+        cv.ellipse( img, (dx+150, dy+150), (40,10), 0, 0, 360, black, -1 )
+        cv.ellipse( img, (dx+27, dy+100), (20,35), 0, 0, 360, white, -1 )
+        cv.ellipse( img, (dx+273, dy+100), (20,35), 0, 0, 360, white, -1 )
+    return img
+
+def main():
+    img = make_image()
+    h, w = img.shape[:2]
+
+    contours0, hierarchy = cv.findContours( img.copy(), cv.RETR_TREE, cv.CHAIN_APPROX_SIMPLE)
+    contours = [cv.approxPolyDP(cnt, 3, True) for cnt in contours0]
+
+    def update(levels):
+        vis = np.zeros((h, w, 3), np.uint8)
+        levels = levels - 3
+        cv.drawContours( vis, contours, (-1, 2)[levels <= 0], (128,255,255),
+            3, cv.LINE_AA, hierarchy, abs(levels) )
+        cv.imshow('contours', vis)
+    update(3)
+    cv.createTrackbar( "levels+3", "contours", 3, 7, update )
+    cv.imshow('image', img)
+    cv.waitKey()
+    print('Done')
+
+
+if __name__ == '__main__':
+    print(__doc__)
+    main()
+    cv.destroyAllWindows()