Added a ad-hoc way of manually specifying primary keys for tables or
views. Useful for materialized views and views where the user know what
is a key
Merge branch 'bugfix/mappingProcessorIteration' of github.com:ontop/ontop into feature/viewKeys

This bugfix must be merged into the viewKeys branch, as otherwise the branch cannot be used on the mappings where it is needed
Added foreign key reading to the view key reader manual "fake" keys
Prints out all foreign keys to the console. Added a view_keys for the
testing.
Merge branch 'develop' of github.com:ontop/ontop into feature/viewKeys
Merge branch 'develop' of github.com:ontop/ontop into feature/viewKeys
Merge remote-tracking branch 'origin/develop' into feature/viewKeys
Removed printing of keys
Merge remote-tracking branch 'origin/develop' into feature/viewKeys
Moved the filename for view_keys from hardcoded to QuestPreferences
Added a preference for disabling the reading of view keys from file. Set
to default false
Merge remote-tracking branch 'origin/develop' into feature/viewKeys

Conflicts:
	reformulation-core/src/main/java/it/unibz/krdb/obda/owlrefplatform/core/Quest.java
	reformulation-core/src/main/java/it/unibz/krdb/obda/owlrefplatform/core/QuestPreferences.java
Merge branch 'develop' of github.com:ontop/ontop into feature/viewKeys
Refactored the reading of user-supplied constraints: Split into a
parsing step and a separate step for adding to metadata. Added simple
unit tests for the class (UserConstraints). Added preference boolean
variable for choosing whether to print the keys registered with ontop.
Made a path in the api from QuestOWLFactory to Quest for introducing
UserConstraints. Added "integration" test that tests UserConstraints and
self-join elimination together. Removed the unnecessary options for
view_keys
Moved user-constraints test to the quest-sesame package
Added a boolean "applyUserCOnstraints" to QUest, QuestOWL and
QuestOWLFactory to avoid passing around null values.
Adds tables referred to by foreign keys in user-supplied constraints to
the list of tables for which metadata is fetched in the
non-full-metadata case. Also some tests for this.
Merged branch 'develop' into feature/userConstraints
Removed old user-constraints configuration file "view_keys.lst"