Streaming: isRelevant wasn't getting executed. Fixes #273

This was my fault; I put `DDG.isRelevant` in the if statement, and it turns out it was getting short circuited and never getting evaluated. Also, I'm not sure why we were using `stringsRelevant`.
Streaming: Removed `console.log`.
Merge pull request #275 from duckduckgo/jag/canistreamit

Streaming: isRelevant wasn't getting executed. Fixes #273