Epic just did the one thing programmers have spent 26 years warning each other will kill a software company, and in tests Epic commissioned, the result opens almost twice as fast as Steam. The thing is throwing out all your old code and rewriting the app from zero. Here's why programmers are so scared of it. Back in 2000, Netscape was the big name in web browsers, and it decided its code was too messy to keep patching, so it started over. That's why there's no Netscape 5. Almost three years…