Implement a custom HystrixPropertiesStrategy plugin

Add a custom HystrixPropertiesStrategy implementation where getCommandPropertiesCacheKey is overridden to return null so that HystrixPropertiesFactory will always generate a new HystrixCommandProperties for each new HystrixCommand instantiation.
Nevermind, as of cf0507a, I've changed it to return a string that is a combination of the CommandKey name and the builder JSON string value.  Human-readable too now as a bonus.