Check for nils
Fix typo in path
Prevent more nil dereferencing
Update SocialTraits.yml template

Trait sets were generated with
traitdb_utils/make_socialtraits_template.rb from Final Columns.xlsx
Added metadata columns to suit references and rename start/end date
Merge pull request #60 from NESCent/socialtraits_updatetemplate

Update import config for social traits and fix nil derefs