Refactor Processors, fix Yajl compatibility

+ Refactor our SanitizeData processor into three separate processors
+ Change weird Processor namespacing
+ Change weird requires in specs
+ Fix YAJL compatibility by preferring vendored OkJson

I wish we could let you use YAJL's "drop-in" JSON replacement, but it appears to have a different API than the `json` gem. OkJson will probably be slower than both options, but it's the only way I see to assure compatibility here.