use gzip

according to docs ruby http should use gzip, using activity monitor I could only verify 6.9MB -> 6.2MB change which is much lower than we expected ... any better way to verify if this works ?

change line 66 + `[0..100]`
change line 113 to `puts "DONE"; sleep` to keep it running/in activity monitor

```
bundle exec ruby ./bin/s3-meta-sync zendesk_i18n-staging:translations testing
```

before:
![screen shot 2014-11-19 at 8 47 40 pm](https://cloud.githubusercontent.com/assets/11367/5119904/cc5e6b9a-702d-11e4-941c-9fa256133a41.png)

after:
![screen shot 2014-11-19 at 8 45 59 pm](https://cloud.githubusercontent.com/assets/11367/5119903/cc5aebe6-702d-11e4-9568-c23cd8f76d58.png)



@anamartinez @ashmckenzie @caquino