Added gzip'ing of scrape FileCache get, sets.

'Sup dudes, I'll stop bothering you soon, I promise. 

So I was scraping the CFR and my cache had 15G in it, and I tested gzip'ing all the files, and that shrank it down to 850MB. Alrightee then! This looked easy to add, to I took a whack. 
Yo yo yo, @twneale - it might be cool to pass that into the constructor too - like how `check_last_modified` works, so you can write code that uses this behavior without telling the user how to set up the env :)