Built from mxnet warp ctc example

Car plate generation code imported from end-to-end-for-chinese-plate-recognition

• OCRIter prefetch to boost training speed
• OCR model prediction
• Blstm implementation

• Captcha model, accuracy 97.6%
• Chinese car plate model, accuracy 98.2% (computed by edit distance)

Mxnet==0.9.5 with baidu warpctc plugin should be installed first:

python infer_ocr_captcha.py
python infer_ocr_plate.py