Use gzip compression of data before uploading to S3

[coreylight]

Use gzip to lower costs on s3 and save time on the network request. May need some benchmarking to make sure we are actually saving time. Can stream to the zlib module once we move to a streaming transport too 😎

[ewindisch]

My implementation of a solution for #4 includes zipping files with zlib (gzip) compression.