add Derek Eder to contributors, update example with api key  and flag for upcoming v0.4 breaking change on returned geometry.
add json dependency to gem task
add api_key to test config yml
tests now updated to expect GeoJSON. All hail the hypnotoa
Version bump to 0.4.0
Regenerate gemspec for version 0.4.0
Update README.md
Update README.md
Update README.md