1.2.0 -> staging

[ultrasaurus]

• Move from Travis to Circle CI
• Update New Relic gem, so as to use the new Error Analytics features
• Upgrade puma to 2.15.3 so it builds on OS X 10.11 OK
• Fix various errors we're seeing in NewRelic:
  • better zip/distance error reporting (fixes NR error: "Undefined method '[]' for nil:NilClass" in QueryBuilder#search_location #265 and NR error: "Stretchy::Errors::ValidationError" in QueryBuilder::search_location #266)
  • stats on nested fields no longer throw a stack trace, but doesn't yet give correct result (NR error: undefined method `each' for nil:NilClass in DataMagic.search #276)
• Remove obsolete RunRailsCops rubocop directive
• Document location field (Querying for a school by name and returning location.lon does not work #227)

[yozlet]