Replace global containers by encapsulating state

Replace every global container with a locally encapsulated/passed one. Examples:

```go
type A struct {
   state ..
}

... subsequent functions become methods on A
```

```go
var readChan  = make(chan ...)
var writeChan = make(chan ...)

func() {
  var container ...
  
  for{
    select {
      op := <-readChan
        ...
      op :=<-writeChan
        ...  
  }
}()
```