[web/debug] remove code broken by session refactoring session.cnx and cnx.check() no longer exist.

[web/debug] Fix check for open sessions itervalues returns an iterator, which never evaluates to False. Regression from 0bb18407c053 "[toward py3k] rewrite dict.keys() and dict.values() (part of #2711624)".

[cwconfig] Remove useless 'ui-cube' configuration option (closes #3728904) The mechanism introduced could never actually be used as it brings dependency loops to the cube graph. Just get rid of it. This reverts commit 4032499c701e.

[test] Use RepoAccess.shell() in unittest_predicates

[devtools] add 'shell' method to RepoAccess, deprecate CubicWebTC's Lets us control the connection's lifetime.

[repo] make extid2eid work with either a session or a connection The only place it should matter is for restoring pending_operations in case of failure. Which is not exercised by the test suite. Here be dragons.

[repository] extid2eid's 'commit' argument no more necessary This removes the need for creating an internal session.

[repository] complete argument is no more needed since we have no more 'true' multisource. It is always false.

[repository] 'session' argument is always given to type[_and_source]_from_eid, make it mandatory and simplify code accordingly

[repository] 'session' argument is always given to extid2eid, make it mandatory and simplify code accordingly

[web/data] Remove broken jquery-json plugin (closes #3590335) Conversion of Date() objects is somehow broken (don't know why beyond that it's due to jquery-json's monkeypatched Date.toJSON() method). Use the now-standard JSON.stringify() instead. http://caniuse.com/#feat=json says it's supported by all browsers, and even IE going back to version 8.

Add missing relation types items in schema global variables Some of these global variables are used, in particular, to control schema views (web/views/schema.py). While they are currently not properly documented (see #3360868), their definition are currently incomplete (e.g. one could reasonably expect to find ``cw_schema`` in ``SYSTEM_RTYPES``). Closes #3486114.

[web] return 403 for Unauthorized, not 401 401 is reserved to HTTP authentication. Just because it's also called "unauthorized" doesn't mean it's the same as cubicweb's Unauthorized exception. Closes #3648809.

[test] update unittest_repoapi to 3.19 api (sic) [jcr: while at it, fix typos and add missing __main__ section]

[test] update unittest_utils to 3.19 api

[test] update unittest_rset to 3.19 api [jcr: use self.admin_access instead of creating a new one each time]

[test] update unittest_rqlrewrite to 3.19 api

[test] update unittest_req to 3.19 api [jcr: use self.admin_access instead of creating a new one each time]

[test] update unittest_predicates to 3.19 api [jcr: use self.admin_access instead of creating a new one each time]

[web/test] port unittest_reledit to RepoAccess API

[web/test] port unittest_magicsearch to RepoAccess API request created in setUp makes context manager usage painful, so create a context manager to do the setup for each test class.

[web/test] use real_error_handling context manager instead of open-coding it

[web/test] port unittest_idownloadable to RepoAccess API

[web/test] remove useless calls to self.request() from CORS tests

[web/test] port unittest_formfields to RepoAccess API

[web/test] port unittest_form to RepoAccess API

[web/test] port unittest_facet to RepoAccess API

[web/test] move unittest_controller to RepoAccess test API