try to follow PEP8

- fixed most important code after checking with flake8
- ignored code which has to be reworked or removed
+ mark unused code with 'TODO: remove ...'

Change-Id: Ic45e541049e391e2853d29cd64bb0963bd9a2125
Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/25053
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>

secop/protocol/messages.py

@@ -80,7 +80,6 @@ REQUEST2REPLY = {
 }
 
 
-
 HelpMessage = """Try one of the following:
             '%s' to query protocol version
             '%s' to read the description