Chiχ Flow to FBPX

Converts a graph in json format to .fbp format.

Used by fbpx for the reverse option.

Usage:

$ fbpx -r flow.json | fbpx -j | \
  fbpx -r | fbpx -j | fbpx -r | \
  fbpx -j | fbpx -r | fbpx -j | \
  fbpx -r | fbpx -j | fbpx -r > flow.fbp