Reverse debugging

Nirvana!!!

For compiled languages, see: Section "GDB reverse debugging".

For JavaScript: stackoverflow.com/questions/17498159/how-to-go-backwards-while-debugging-javascript-in-chrome-sources-debugging/74968631#74968631

What it adds on top of reverse debugging: not only can you go back in time, but you can do it instantaneously.

Or in other words, you can access variables from any point in execution.

TODO implementation? Apparently Pernosco is an attempt at it, though proprietary.