Feature: clear request log with Control+L

[fvsch]

I tried implementing it with console.clear(), but in my tests the results can be very strange.

I suspect if you used a mix of stdout.write, stderr.write and console.log, then calling console.clear will only be able to overwrite some of stdout, and other stuff will remain visible.

It might be doable with better results if I avoid using console.log altogether and do all logging with stdout.write, and then overwrite stdout contents manually. Something to explore.