* some integrity checking that was previously implemented in Python was

  moved to the SQL backend.  This includes some constraints, and

  referential integrity.  Some consequences are that:

  - disabling integrity hooks no longer disables those checks

  - upgrades that modify constraints will fail when running on sqlite

    (but upgrades aren't supported on sqlite anyway)

* for easier instance monitoring, cubicweb can regularly dump some statistics

  (basically those exposed by the 'info' and 'gc' views) in json format to a file

User-visible changes

--------------------

* the use of fckeditor for text form fields is disabled by default

* the 'https-deny-anonymous' configuration setting no longer exists

* the way to run tests on a postgresql backend has changed slightly, use

  cubicweb.devtools.{start,stop}pgcluster in setUpModule and tearDownModule

* the Connection and ClientConnection objects introduced in CubicWeb 3.19 have

  been unified.  To connect to a repository, use:

  session = repo.new_session(login, password=...)

  with session.new_cnx() as cnx:

      cnx.execute(...)

  In tests, the 'repo_cnx' and 'client_cnx' methods of RepoAccess are now

  aliases to 'cnx'.

  and run ``cubicweb-ctl upgrade`` to update it.  Likewise, remote cubicweb-ctl

  shell is no longer available.

* cubicweb.toolsutils.config_connect() has been removed