Include nascent curator scaffolding.

The curator doesn't do anything yet; rather, this is the type
definition including the anciliary testing scaffold.

Improve Makefile and Git developer experience.

The top-level Makefile was a bit overloaded in terms of generation of
assets and their management.  This has been offloaded into separate
Makefiles.

The Git developer experience sucked due to lack of .gitignore
policies.

Also: Fix faulty skiplist naming from old merge.
Merge pull request #93 from prometheus/feature/storage/compaction

Include nascent curator scaffolding.