#4 Check depedencies for optional CDK

[Joerg Kurt Wegner]

>does cdk no longer use or
> require this, so that it's joelib's instructions that
are out of date?

Yes, again...

Joerg, can you have a look at it? CDK no longer has
JSX... i'm not sure if JOELib needs it for itself, or
just for the CDK bits... But in any case, please update
the build instructions.