Classpath command added

I've added a "classpath" command to modify the classpath of the shell.

This command enables you to run java code from any location.

This brings us a lot closer to the 0.2 release goal of running java code from any place!

E.g. i create a small HW (hello world) class and placed it in the root directory of my tftp server. Then i start JNode on my test PC and executed the following commands.

> bootp eth0
> classpath add tftp://[my server ip]/
> HW

and i see my "Hello world".

You can also clear the classpath (to refresh the classloader) using:

> classpath clear

If you now change the code of the HW class, and re-execute:

> classpath add tftp://[my server ip]/
> HW

Then you will execute the new code.