[pyramid/security] use cryptographically secure random generator
Based on django source code in case SystemRandom is not available.
According to python documentation:
https://docs.python.org/2/library/random.html
> Warning
> The pseudo-random generators of this module should not be used for security
> purposes. Use os.urandom() or SystemRandom if you require a cryptographically
> secure pseudo-random number generator.
.. _web_module:
:mod:`cubicweb.web`
===================
.. automodule:: cubicweb.web
Exceptions
----------
.. autoexception:: DirectResponse
.. autoexception:: InvalidSession
.. autoexception:: PublishException
.. autoexception:: LogOut
.. autoexception:: Redirect
.. autoexception:: StatusResponse
.. autoexception:: RequestError
.. autoexception:: NothingToEdit
.. autoexception:: ProcessFormError
.. autoexception:: NotFound
.. autoexception:: RemoteCallFailed