Questions about JsBulitIn

The JsBuiltIn system makes cross-platform development difficult, since:

- The scripts to regenerate the bytecode are written for the windows command shell.
- x86 isn't even supported on Mac, etc.

Also, dealing with bytecode regeneration is a constant source of conflicts and annoyance.

So a couple of questions for the OG Chakra devs:

1. What advantage does the JsBulitIn system give (as opposed to just keeping it in C++)?
1. Why is there different byte code for x86/x64/jit/no-jit?

@pleath @boingoing @jackhorton