Some external packages are necessary for dtest usage:

	- Paramiko which is a pure python SSH implementation
		http://www.lag.net/paramiko
                (paramiko requires PyCrypto http://www.amk.ca/python/code/crypto.html)
	- PyTAP which a Python Module which implements Test Anything Protocol
		http://svn.codesimply.com/projects/pytap
  		http://en.wikipedia.org/wiki/Test_Anything_Protocol
	- Pexpect (not used yet)
		http://pexpect.sourceforge.net
