Enable GZIP

[nodanaonlyzuul]

This was first talked about in #54

curl -sH 'Accept-encoding: gzip' -g http://example.com
# returns compressed garbage :)

curl -sH 'Accept-encoding: gzip' -g http://discovery-api-dev.us-east-1.elasticbeanstalk.com/api/v0.1/request/deliverylocationsbybarcode?barcodes[]=33433035124316
# returns uncompressed text :(

We should enable gzip compression in nginx.
I don't know why elastic beanstalk would default to NOT enabling gzip compression in nginx
but it should be easy to override the .conf file using .ebextensions.

Open Question

Do most HTTP client libraries send "Accept-Encoding: gzip, defalte" by default?