Randomize delays between all requests

It'd be great to randomize delays between requests Dux-soup makes at any selected speed. E.g. not strictly N seconds, but N plus/minus 1-2 seconds. No need to add a control to enable/disable, it should just be enabled in there. This would represent human's behavior more accurately.

So far it randomizes delays only if you select "Random: between X and Y per hour" speed where X and Y differ too much, and both X and Y are low. When you select any other speed it makes the same delay of N seconds between requests where N depends on selected speed - that's easy traceable.

This refers to all operations, including scanning, visiting, messaging - everything.