jpterm is slow with large json files

jpterm takes a lot of time to load and perform queries on large json files. Here's an example of such a big file : https://gist.github.com/thg1101/8f11e3c2c7274f114536

I'm suspecting that something is wrong with the python implementation or the rendering code because loading the file and performing queries with it works reasonably fast with the JavaScript implementation.
