add hint for debian/argparse

Signed-off-by: Nico Schottelius <nico@kr.ethz.ch>

README

@@ -86,13 +86,23 @@ cdist was tested or is know to run on at least
  * SSH-Server
 
 
-## Getting cdist
+## Installation
+
+### Preperation
+
+Ensure you have Python 3.x and the **argparse** module installed on
+the machine you use to **deploy to the targets**.
+
+#### Debian
+
+    aptitude install python3 python3-setuptools
+    easy_install3 argparse
+
+
+### Get cdist
 
 You can clone cdist from git, which gives you the advantage of having
 a version control in place for development of your own stuff as well.
-
-### Installation
-
 To install cdist, execute the following commands:
 
     git clone git://git.schottelius.org/cdist