Partially reverts changes of 9d0255e7.
Added helper methods to Room which transform the ContentGroup collection
from Set to Map. Content IDs are now removed from groups when Contents
are deleted.

Replaced the following events with StateChangeEvent:
* FeatureChangeEvent
* LockFeedbackEvent
* LockQuestionEvent
* LockVoteEvent
* LockVotesEvent
* PiRoundCancelEvent
* PiRoundDelayedStartEvent
* PiRoundEndEvent
* PiRoundResetEvent
* StatusRoomEvent
* UnlockQuestionEvent
* UnlockVoteEvent

Removed the following redundant events:
* DeleteAllLectureAnswersEvent
* DeleteAllPrepareationAnswersEvent
* DeleteAllQuestionsAnswersEvent
* DeleteAllQuestionsEvent
* LockQuestionsEvent
* UnlockQuestionsEvent
* UnlockVotesEvent

To trigger events, some code was migrated to use EntityServices instead
of directly accessing Repositories.

The hook methed was never called.

The event is now published for every single patched entity.

`modifyRetrieved` can be overriden to modify Entities before they are
returned by CRUD methods.

Mock the correct method.

Implements #30.
Fixes #29.

Patching of child objects is now handled.

This was broken by refactoring of events.

Tom Käsler authored 6 years ago and Daniel Gerhardt committed 6 years ago

See merge request !96

A new event for full updates has been added.

The entity is now stored in a separate property.

Additionally, roomId is used instead of Room object for legacy
RoomEvents.

@EventListener is used for handler methods instead of implementing
a visitor interface.

* Prefer simple IDs over entity types for method parameters
* Avoid use of obsolete v2 classes in service and repository layers
* Optimize imports

The format for answers is now set based on the content's format.

Tom Käsler authored 6 years ago and Daniel Gerhardt committed 6 years ago

See merge request !94

Migration version now falls back to -1 if no document exists.

A log file path can now be set via `arsnova.log.file` Java system
property. If a log file path is set, the threshold for STDOUT logging is
increased to WARN.

Support for java system properties to tune logging have been added:
* arsnova.log.exceptions
* arsnova.log.level
* arsnova.log.level.root
* arsnova.log.level.spring
* arsnova.log.properties

Tom Käsler authored 7 years ago and Daniel Gerhardt committed 6 years ago

Currently supports finding contents by `roomId`.

Consistently use singular for packages which contain mixed kinds of
classes. Moved a few classes to packages that better fit them.