don't use tabs in Python code

git-svn-id: https://www4.informatik.uni-erlangen.de/i4svn/danceos/trunk/devel/fail@1310 8c4709b5-6ec9-48aa-a5cd-a96041d1645a

doc/coding-style.txt

@@ -4,6 +4,12 @@ Coding Style for Fail*
 You may violate/break any of the following rules if you have a good reason to
 do so, e.g., if readability is notably enhanced.
 
+For Python code, try to stick to <http://www.python.org/dev/peps/pep-0008>.
+Especially use 4 spaces per indentation level, and don't mix tabs and spaces
+for indentation.
+
+The following style rules apply to C/C++ code:
+
  - Language (comments, SVN commit messages, "temporary" stuff): English
    (without exception)