Send posts to TSAF as gzip'd content

This will matter when stuff is going over the VPN. I have tested this and it seems to work out with the following patch applied to opentsdb: https://groups.google.com/forum/#!topic/opentsdb/JQ7azVR5x_g
Don't need the NewReader()
Don't need to flush because close flushes; return on gzip err, style changes
Merge pull request #9 from StackExchange/gzip

Send posts to TSAF as gzip'd content