fix tests broken by lgdb update

[migration] Ignore IOError from readline.write_history_file (closes #2106621) We already ignore them when reading the histfile, no reason writing it back should be any different.

[migration] make remove_cube('foo') not fail if foo is already removed. Closes #2106532

[cwconfig] absolute import (closes #2091068)

[schema sync] Update repo._type_source_cache when renaming an entity (closes #2094470) When an entity type is renamed as part of a migration, it leaves stale entries in repo._type_source_cache, which makes subsequent operations on those entities fail (they look for the old entity name instead of the new one).

[facets] forcing a fixed height to the group is a bad idea: the container will not properly overflow

[views/tabs] tests absolutely want an alt attribute (even if meaningless)

[navigation] provide a link back from the full view to the paginated one provide a better marker for navigation induced call detection Closes #2103687

[sorted navigation] refactor code so that when an attribute is found, nb_chars may be recomputed anyway according to variable type

[reledit] implements entity_call instead of cell_call

[merge] backport stable

[skel] default debian/rules use pysupport to compile python files Drop the unused python-dev build-dependency (only necessary for binary extensions)