Demo for CRNN

[Charles-258]

change the demo for crnn

[fengyuentau]

Demos look good to me, but some minor changes have to be done:

1. Add your GIF to README.md in root.
2. Squash your commits into one with the following commands

   git reset HEAD~8 # 8 is the number of your commits
   git add .
   git commit -m "crnn demo"
   git push -f

[Charles-258]

I deleted the branch crnnctc by mistake which automatically closed this pr.
But I have created a new pr RELATED PR68.