Allow empty arrays and hashes in structured facts

We were getting validation errors in factmap-to-paths code due to the lack
of proper handling for empty hashes and arrays. This patch drops those branches
quickly and now moves onto the next element.

Signed-off-by: Ken Barber <ken@bob.sh>
Merge pull request #1021 from kbarber/maint/master/allow_empty_hashes_and_arrays_in_sfacts

Allow empty arrays and hashes in structured facts
got some of the json "restructuring" stuff done, need to connect it with
data coming from the DB

Rename factset app from copy/paste problem
(PDB-711) Add factsets endpoint to V4 PuppetDB API

This pull request adds the /factsets endpoint specified in the
"Structured Facts Design and Plan" document circulated to Puppet-dev
on June 30.  The response is a list of maps, each describing the
facts, environment, and time of most recent fact submission for
an agent node.