Data importing too slow without threading

[xros]

I found it would be way slow if importing massive data into ES.

By default jsonpyes does not use Epoll, so it runs on one thread. The I/O of it is very slow.

It would take more than 5 hours to import 3GB data to ES.

There should be an improvement.

[xros]

This was solved by me.
#3

But the efficiency was not improved too much. Maybe it works greater in good servers.

Let's see. 😃

[xros]

almost 5 times faster than before.

Here's the pull request. #17

Thanks to all people's contribution to this project 😃