Compiling

$ glide install
$ go build -o scat ./cmd

Running all tests:

$ tools/test

Writing a new proc

delegator: a(b) calls b, filters its results

In a.Process():
```
 // ...do things before
 ch := b.Process(c)    // within current goroutine
 out := make(chan Res) // after ch
 go func() {
   defer close(out)
   // ...consume ch
 }()
 return out
```
In a.Finish(): must call b.Finish()

When either a.Process() or a.Finish() (or both) does nothing else than delegating to b, then a should be a struct that embeds Proc to inherit those methods and benefit from implicit delegation.