Add more example code on new geobin page

[ungoldman]

For now we only have a curl example:

curl -X POST \
-H "Content-Type: application/json" \
-d '{"lat":45.5218,"lng":-122.6773,"rad":1000}' \
geobin.io/NUMGz0br0Y

As suggested by @jyaganeh in #89, it would be nice to have samples for other languages, e.g. Ruby, Python, JavaScript, Go.