how to decompress

Hi! SoA is a great idea! 
But how to decompress? I can't understand the syntax. Could be great if the readme explained  a bit more about calling syntax. 

```
$ python xfjson.py -d output.json reversed.json
usage: xfjson.py [-h] [-b] -t DOTRANS [-d] inFile outFile
xfjson.py: error: argument -t is required
```
