EZP-21515: removed UserMetadata::CREATOR

The original creator of a content object is something that we might not
have in legacy since archived versions might be removed. Therefore, we
remove that notion for now. It might be reintroduced with an enhancement
request.
Fixed EZP-21515: Missing Legacy Converter for UserMetaData Criterion
EZP-21219: Integration test for archived versions
Merge pull request #498 from MLoureiro/ezp21219_integration_test

EZP-21219: Integration test for archived versions
Doc: Mention where to find Content names in all languages
Doc: Some api doc cleanup on Content

Make sure Content is always refered to as "Content object", and some other minor doc improvments.
EZP-21515: extra documentation about VersionInfo->creatorId being the 'modifier'
Merge pull request #502 from ezsystems/content_name_doc

Content name doc
Merge pull request #501 from patrickallaert/EZP-21515

Fixed EZP-21515: Missing Legacy Converter for UserMetaData Criterion
Fix EZP-21550: Changing owner, clearing cache needed for Owner(Self) to work
Merge pull request #504 from ezsystems/EZP-21550

Fix EZP-21550: Changing owner, clearing cache needed for Owner(Self) to ...
[PHPDoc] Clearify misisng StateGroup in light of EZP-21501
Revert "[PHPDoc] Clearify misisng StateGroup in light of EZP-21501"

This reverts commit 97617bef9336c3b3f6d014551e48520e6c56ee99.
Changed: Fail tests on DB connection issue

Not doing so, all tests are skipped and the build is considered as
successful by Travis.
Fixed: Incorrect PostgreSQL fixture schema
Merge pull request #508 from patrickallaert/FailTestsOnDBConnectionIssue

Changed: Fail tests on DB connection issue
Merge pull request #509 from patrickallaert/FixIncorrectPostgreSQLFixtureSchema

Fixed: Incorrect PostgreSQL fixture schema
Fixed typos
Typo Fixing EZP-21568
EZP-21278: check only content/read if current version was requested