(maint) Improve default output of structured facts.

For map and array values, cfacter attempted to maintain compatibility
with facter's output. Unfortunately, facter's output makes it really
hard to read map and array values.

This change "pretty prints" map and array values by default, making the
output much easier to read.
Merge pull request #174 from peterhuene/output/formatting

(maint) Improve default output of structured facts.