Buffered Ports 

Re-issue of pull request https://github.com/planthaber/rock-webapp/pull/11 against master
The only place where having an extremely confusing @readerwriter instance variable helps is in #connected?. I don't believe this is really worth it. Split @reader and @writer and create yourself

```
def reader_or_writer
   @reader || @writer
end
```

accessor for the only case where it helps