KaitaiStream is abstract?
I've been trying out Kaitai Structs and it looks very impressive.  However, I'm getting an error:

I copied the code directly from your site:
```java
DnsPacket data = new DnsPacket(new KaitaiStream(dns_bytes));
```
However, when I try to build this, I get the following error:

```java
java:[53,77] error: KaitaiStream is abstract; cannot be instantiated
```
I'm not a great Java developer, but it seems like this should work.  Any suggestions?
I am using Kaitai version 0.8. 
