* Receive class that wraps PartialFunction, to avoid
scary scala types
* move AbstractActorContext to AbstractActor.ActorContext
* converting docs, many, many UntypedActor
* removing UntypedActor docs
* add unit test for ReceiveBuilder
* MiMa filters
* consistent use of getContext(), self(), sender()
* rename cross references
* migration guide
* skip samples for now
* improve match type safetyi, add matchUnchecked
* the `? extends P` caused code like this to compile:
`match(String.class, (Integer i) -> {})`
* added matchUnchecked, since it can still be useful (um, convenient)
to be able to do:
`matchUnchecked(List.class, (List<String> list) -> {})`
* eleminate some scala.Option
* preRestart
* findChild
* ActorIdentity.getActorRef
The idea is to filter the sources, replacing @<var>@ occurrences with
the mapping for <var> (which is currently hard-coded). @@ -> @. In order
to make this work, I had to move the doc sources one directory down
(into akka-docs/rst) so that the filtered result could be in a sibling
directory so that relative links (to _sphinx plugins or real code) would
continue to work.
While I was at it I also changed it so that WARNINGs and ERRORs are not
swallowed into the debug dump anymore but printed at [warn] level
(minimum).
One piece of fallout is that the (online) html build is now run after
the normal one, not in parallel.
