Create python_tutorial.rst
Create python_tutorial.rst

Former-commit-id: ee5992e43b82b6a81e28c589e76a14dac622beca
shuheik/dynet,clab/dynet,clab/dynet,shuheik/dynet,danielhers/dynet,shuheik/dynet,danielhers/dynet,xunzhang/dynet,clab/cnn,danielhers/dynet,clab/dynet,chunyang-wen/dynet,shuheik/dynet,shuheik/dynet,xunzhang/dynet,clab/cnn,shuheik/dynet,clab/dynet,clab/dynet,clab/cnn,clab/dynet,danielhers/dynet,chunyang-wen/dynet,xunzhang/dynet,chunyang-wen/dynet,xunzhang/dynet,clab/dynet,shuheik/dynet,danielhers/dynet,danielhers/dynet,chunyang-wen/dynet,danielhers/dynet