Changements

gs-reactor: Use Observables to define metabindings
– Use Observable<Snapshot<Generic>> to define a forEach and
 Observable<Optional<Context>> to define a select metabinding.
– Adapt the existing applications to this change.
– Allow sorting of Snapshots.
– Dispose subscriptions to the observables used in metabindings.
 (commit: 7b48c63)

gs-api: Snapshot: Avoid side-effects in Observables
 (commit: 741cced)

gs-api: Snapshot: Use TreeSet/HashSet instead of concurrent sets
Concurrent sets should not be necessary with RxJava.
 (commit: 951e75b)

gs-api: Snapshot: Add removals to result of getIndexedElements()
This allows getting all the changes in only one method. However, it
can’t be used in MetaBinding because, for each added child Context, an
Observable indicating when to create or delete an associated DOM node 
depending on the values of the ObservableValues returned by the
Switchers is created.
 (commit: 8ed4165)

gs-api: Snapshot: Add javadoc
 (commit: 6a21fdd)

Refactor: getAdds/RemovesObservable() -> getAdds()/getRemovals()
 (commit: 62964fd)

gs-api: Snapshot: Fix warnings in Javadoc
The warnings are treated as errors by Maven.
 (commit: 542514e)

Do not return ObservableValues in methods in DefaultCompositeInheritance
Return Observable<Optional<T>> instead of ObservableValue<T> for 
getObservableAttribute, getObservableHolder, etc.
To return an ObservableValue, it’s necessary to use the
toObservableList() method from Snapshot, which is deprecated since it
does not allow unsubscription from the Observables subscribed to in the
method.
Emit items of type Optional<T> rather than T because Observables can’t
emit nulls.
 (commit: 08a081e)

Use Set instead of List in a contains test
To slightly improve performance…
 (commit: 361ef31)

Use memoization in more places, use share() instead of
replay().refCount()
Store Snapshots and Observables so the same instance is returned by
successive calls. This (partially) prevents exponential growth of the
number of Observables subscribed to a given Observable.
share() is the appropriate operation needed, not replay().refCount()
(the observables were not actually shared previously so it did not
matter…).
 (commit: 43e98d6)

Memoize getAttributes/getHolders
 (commit: a0c0135)

remove not-to-track files
 (commit: 4294a2f)

restore .classpath files
 (commit: 2f9f24b)

clean wd
 (commit: 8565e9e)

merge
 (commit: 666cf25)

CamLiveRetriever now works
 (commit: 091e361)