create a Dockerfile ,with opencv3.2

[xlight]

what changed add: Dockerfile modify: according #https://github.com/liuruoze/EasyPR/issues/152 chars_identify.cpp load去掉ml::ANN_MLP plate_judge.cpp load去掉ml::SVM svm_train.cpp load去掉cv::ml::SVM

[liuruoze]

Good work, but in the new version, we have used a macro to judge the OpenCV version, and solved the Opencv3.2 incompatiable

[liuruoze]

请仅保留dock作为pr内容，然后合并。后续的dock的更新也请助力！