[merge] backport stable fixes

[test/ldapsource] backout 192a748550c7 which broke RQL2LDAPFilterTC

[rset] make sure rset.description is always a list It's more consistent, and avoids pylint warning "Instance of 'tuple' has no 'append' member"

[schema] edit syntax tree instead of playing with strings for RQLExpressions Lets us support more complex expressions involving e.g. "HAVING" clauses. Closes #3202855

[py3k] note about future warning on __eq__ vs __hash__ Closes #3179561.

[formfields] py3k kill future compat warning Related to #3179561.

[entity] do not raise an AssertionError if the kwargs given to set_relations/attributes is empty Regression was introduced in 3.16 with the new cw_set API. Old set_relations and set_attributes methods did not crash on empty kwargs. Closes #3104019.

[packaging] setup.py: don't exclude skeleton/debian/* from being installed Closes #3192725.

[tests/hooks/integrity] kill old and empty skipped test

[server/session] demote log to debug It can pollute the log very fast. Closes #3203391.

[test] use assertCountEqual instead of assertItemsEqual

[server] fix a number of typos, mostly in docstrings

[skeleton] Install cubes README in Debian packages (Closes #3171971)

[debian] Build-Depends on python-unittest2 | python (>= 2.7) Closes #3175895.

[doc] typos and reformulation

[doc] additional documentation about pip install under both Windows and Debian

spelling: rollbacked -> rolled back

Added tag cubicweb-version-3.17.9, cubicweb-debian-version-3.17.9-1 for changeset 5668d210e49c

merge two default heads

[pkg] prepare 3.17.9

Use the list of sources instead of an iterator in update-feeds looping task This prevents RuntimeError due to dictionary size change that may occur (as a result of a new source being added) during iteration. Closes #3155843.

[security] fix dumb attribute error when inserting read security. Closes #3196891 This has gone undetected because of erroneous tests...

[entity] give a default reasonnable __eq__ and __hash__ to Entity Using the eid. Closes #3179560.

[debian] add some Breaks for backwards compatibility removal The person and comment cubes used to import the cubicweb.mixins module. The inlinedit cube relied on String.startsWith in javascript.

[js] remove 3.9 bw compat (where apparently unused) - cubicweb.ajax.js - loadxhtml: form.callback support removal - removal of top-level functions: preprocessAjaxLoad, reloadBox, replacePageChunk, loadxhtml - cubicweb.compat.js: - map is undeprecated (jquery.map being not an acceptable replacement) - removal of noop, contains, findValue, filter, addElementClass, removeElementClass, hasElementClass, KEYS mapping - htmlhelpers.js: use non-deprecated functions cw.urlEncode - cubicweb.js: - removal of startsWith and endsWith monkeypatches - note deprecated but still used stuff (for action) - test_utils.js: use cw.utils.sliceList instead of global function Closes #2782004.

Rename cleanup_interface_sobjects into cleanup_unused_appobjects Interfaces are gone in 3.18 Related to #2782004.

remove cw 3.9 bw compat (bw compat other than the interface -> adapter changes) - cwconfig, doc/admin/setup: docstring adjustment wrt 3.9 & virtualenv - testing/rst: windmill (which is gone from the testing infrastructure) - other docs: "stuff introduced in 3.9" cleanup, as we don't care about the version old features were introduced - server/hooky.py: bw compat for propagation hooks - server/schemaserial.py: pre CWUniqueTogetherConstraint migration support - web.__init__.py: dumps bw import - autoform.py: .action ppty is gone, also deprecate set_action and get_action - baseviews: CSVView.subvid gone long ago, secondary view removal - primary.py: _render_attribute & _render_relation signature change - reledit.py: rvid/default_value bw compat, should_edit_* dropped - webconfig.py: resourcefile is gone - formfields.py: old vocabulary handling - request.py: build_ajax_replace_url, external_resource Related to #2782004.

remove 3.9 bw compat In cw 3.9, interfaces are deprecated and replaced with adapters, yielding a lot of bw compat in many places -- most if this patch is concerned with the interface bw compat - cwvreg: interface cleanup - doc/adapters.rst: interface cleanup - entities/adapters.py, wfobjs.py: interfaces bw compat - entity.py: interfaces bw compat, also get_value, delete, attr_metadata, has_perm, set_related_cache, clear_related_cache, clear_related_cache, related_rql - predicates.py: score_interfaces & implements - interfaces.py & mixins.py: 100% gone - view.py: implement_adapter_compat, unwrap_adapter_compat - calendar.py, editcontroller.py, ibreadcrumbs.py, navigation.py, xmlrss.py: interface bw compat - treeview.py: salvage one function from mixins.py Related to #2782004.

remove 3.8 bw compat - cwconfig: old keys such as depends_cubes and non-dict dependencies - cwctl: fall back to docstring if no short descr, forget 'short_descr' - dbapi: session_data, get_session_data, set_session_data, del_session_data - dbapi & testlib, session: eid_key is gone - migractions: cachekey is gone - doc/datamodel/definition, schemaserial: BoundConstraint -> BoundaryConstraint - formwidgets: separator - primary view: render_entity_metadata Related to #2782004.

[hooks/security] Defer entity permission checks to an Operation. Some of these checks may currently happen twice within the same transaction and be costly. This should be semantically safe. If people rely on some internal transaction ordering to be allowed early (thus pass) while the condition wouldn't be met at precommit time, their application is broken. It however seems unlikely to happen in the real life (tm). Closes #2932033

[schema] drop very old bw compat (pre 3.5.10) Closes #2925085.

[devtools,etwist] rename TwistedConfiguration to WebConfigurationBase (follows #2919310)