Rev. 2f7c03d added a second admin user (id 2), the 'human' one, on
top of the 'technical' one (id 1, also known as the superuser).
Basically, all calls to _is_superuser() should have been changed to
_is_admin(). They weren't. As a consequence, some features that
were previously available for the admin weren't anymore (e.g.
tours).
This rev. replaces all calls to _is_superuser() by calls to
_is_admin().
This is done in order to enable the tour service only for the
superuser. Commit 6ef1644a7b changed the meaning of `is_admin`
to achieve this but broke the fact that some features of the debug
manager are available to admin and not only to the superuser. Anyway
a `is_admin` key should mean that the user is in the admin group.
We could have checked client side that the uid is equal to 1 but
adding a `is_superuser` key is more elegant and easier to grep.
Also fix the only occurence of a uid check in the weblcient.
This reverts commit 6ef1644a7b.
Aaron Bohy