New version of primer with comments accounted for

In this version I have taken of the comments from Fabien and from ??
About the wrong example.

The comment from Rotan seemed to have been taken care of on the mailing
list, as well as the one by Kevin.
The latter I did not add to the primer comments as it referred and
reiterated the one from Rotan.

All comments have been added to the tracker.

Kai