Changes for Tensorflow 2.5.0

Fix problem for XML files which additional tags

Update training.rstPrevious link to the Tensorflow 1 Detection Model Zoo,https://github.com/tensorflow/models/blob/master/research/object_detection/g3doc/detection_model_zoo.md, leads to a page that didn't exist anymore (Error 404). The new link to the Tensorflow 1 Detection Model Zoo should be:https://github.com/tensorflow/models/blob/master/research/object_detection/g3doc/tf1_detection_zoo.md.

Update README.md

Removed `,`s in `conda install` which throw an error

Fix missing images

Updated to TensorFlow 1.14

added cythonwhile executing "make" command in "COCO API installation" in linux ubuntu got  "gcc: error: pycocotools/_mask.c: No such file or directory"this thread :cocodataset/cocoapi#141solved the issue ie: after installing cython

added cythonwhile executing "make" command in "COCO API installation" in linux ubuntu got  "gcc: error: pycocotools/_mask.c: No such file or directory"this thread :cocodataset/cocoapi#141solved the issue ie: after installing cython

Minor fixes and updates