make safeRange lt/lte/gt/gte aware

[juliangruber]

what is an appropriate file to add tests for that? Or should I create a new one?

[dominictarr]

there is another range test, add it to that, or if it's getting too long, create a new file.

[juliangruber]

you mean test/streams-sublevel-key-value.js? I was wondering about this one because it also passen when you remove the options objects from the create*Stream calls