Fixes from roland's review.
Migrated Search to keep actual topics + categories on children.

* Added DOT-based supervisor tree viewing with DebugActor
* Moved Topic/Category actors to be their own beings
* Moved splitting into its own actor.  While splitting, Topic nodes can still respond to queries.
* Startup still has timeing issues:  I.e. tree is not loaded immediately.
* `NodeManager` now knows how to alter the state of a node in the search index.  All node creation and
  storage should go through him.
* Can no longer save additional hotels in topics, will work on this shortly.
Set up default logging.
* Unify SearchQuery API form front-end to backend
* Fix bug in cache where 'sender' wasn't grabbed at the correct time, and errors ensued
* First attempt at fixing the TopicSplitter code.
* First attempt at moving DB worker outside the node manager for safety.
Messages are now held for a given node when it is in transition.

Additionally, Topics are now succesfully saved, although categories are not...
Fixes peristence to actually work.

During Become/Split we still have some flagellation where we don't clean up after ourselves.
Fixed issue with race condition and splittig nodes.