Underscore's stores Date.now(), and Lolex cannot replace it

[danny-wu]

Underscore 1.6.0 to 1.8.3 stores Date.now, mandating Date.now to be stubbed before loading Underscore for fake clocks to work. Affected functions include _.debounce, _.throttle, and probably more.

This is an issue with Underscore, not Lolex. Lolex can work around this by replacing Date.now upon installation, but this will end up faking Dates created before installation and end up breaking other, more valid, uses.

Underscore no longer uses Date.now in master, and lodash seems to work as well. This issue is just here for informational purposes.