add StringIO.writeline, improve StringIO.multicomm

- StringIO.writeline sends a command and does not expect a reply
- StringIO.multicomm and BytesIO.multicomm is improved in order
  to insert individual delays in between lines and individual
  noreply flags

+ fix a bug in tutorial_t_control
+ improve readability of frappy.lib.classdoc.indent_description

Change-Id: I9dea113e19147684ec41aca5267a79816bbf202c
Reviewed-on: https://forge.frm2.tum.de/review/c/secop/frappy/+/32267
Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>

doc/source/tutorial_t_control.rst

@@ -405,7 +405,7 @@ Appendix 2: Extract from the LakeShore Manual
     Reply                  <range> *term*
     **Operation Complete Query**
     ----------------------------------------------
-    Command                *OPC?
+    Command                \*OPC?
     Reply                  1
     Description            in Frappy, we append this command to request in order
                            to generate a reply