[tests] Add a webtest based TestCase class Closes #4002134

[tests] Move 'anonymous_allowed' property from CubicWebServerTC to CubicWebTC The effective set of the property on the config is now done later that before, ie at the end of CubicWebTC.init_config instead of before. It is believed not to have an impact on the test suites that uses `anonymous_allowed`. Related to #4002134

[compat] Remove imports of "any" and "all" from lgc (closes #4306044) They're builtin since python 2.5.

[css] Remove the `div` tag specification of the pendingDelete css rule The HTML tag was changed by e2f96b16c3bd from a div to a span without changing the css rule accordingly. Closes #4285248.

[cwvreg] cleanup the event manager when reloading modules Closes #3848995 The event manager callbacks are not cleaned during reloading. So the callback defined in the reloaded module appears twice (old and new version). This may cause problem when the old version is called.

[test] Add missing attribute 'add' permission in test schema Silences yams warning.

[facet html] Add surrounding div with "facetBody" class to "has_text" facet. This makes its html structure consistent with the other facets and fixes both css and a javascript behaviour (hide the facet body when clicking on its title). Closes #3797501.

[cwctl] don't prompt for cube options in automatic mode Closes #3984223

[serverctl] fix default value for db-init config-level Otherwise cubicweb-ctl db-init --automatic complains that "--automatic and --config-level should not be used together" when they weren't. Closes #3984336

[web] Return useful error messages when exceptions arise in ajax controllers (closes #3932503) The call to super() in RemoteCallException passes 'reason' all the way to python's Exception.__init__() which is then stored in Exception.args. This way, CubicWebPublisher.ajax_error_handler() gets a useful error message when calling unicode(exc). The change to uilib is just to prepend the exception type name. Just a small improvement.