We now expose reactive interfaces to facilitate reactive repository support in store-specific modules. Spring Data modules are free to implement their reactive support using either RxJava 1 or Project Reactor (Reactive Streams). We expose a set of base interfaces:
* `ReactiveCrudRepository`
* `ReactiveSortingRepository`
* `RxJava1CrudRepository`
* `RxJava1SortingRepository`
Reactive repositories provide a similar feature coverage to blocking repositories. Reactive paging support is limited to a `Mono<Page>`/`Single<Page>`. Data is fetched in a deferred way to provide a paging experience similar to blocking paging.
A store module can choose either Project Reactor or RxJava 1 to implement reactive repository support. Project Reactor and RxJava types are converted in both directions allowing repositories to be composed of Project Reactor and RxJava 1 query methods. Reactive wrapper type conversion handles wrapper type conversion at repository level. Query/implementation method selection uses multi-pass candidate selection to invoke the most appropriate method (exact arguments, convertible wrappers, assignable arguments).
We also provide ReactiveWrappers to expose metadata about reactive types and their value multiplicity.
Projection types annotated with @ProjectedPayload can now be used as parameters for @RequestBody annotated Spring MVC controller method parameters.
Accessor methods will be translated into JSON path property expressions which can be customized by using the @JsonPath annotation. The methods are allowed to return simple types, nested projection interfaces or complex classes which will will be mapped using a Jackson ObjectMapper.
Switched to new Querydsl 4 artifacts and adapted to changed package names and API changes.
Cleaned up some JavaDoc and APIs in QuerydslBindingsFactory and QuerydslBinderCustomizer.
Refreshed the copy of AnnotationTransactionAttributeSource to pull in the JTA 2.1 support introduced in the Spring Framework class. Opened up a ticket [0] to improve Spring Framework to eventually be able to ditch the copies to prevent such scenarios in the future (the missing feature introduced that is).
