switch from internal Throttle to guava's RateLimiter. #229
as we bumped from guava 11 to 14, had to resolve the SystemUtils's use of
removed guava methods (already fixed in master)
Merge pull request #230 from jasobrown/1.1

Merge 1.1.a into 1.1

reviewed by @timiblossom
Merge branch '229' into 1.1
rev number