There are a few kinds of errors that are very confusing.
1. Errors raised in nextTick
2. Errors emitted on the "error" event
3. RangeErrors that crash the program (or anything without a stack trace)
Long traces will make make these better, of course. In the meantime, this
adds a few handy signposts (in the form of better error reporting and
comments on the otherwise inscrutable code printed to the terminal) that can
help new users find the cause, or at least, ask for help more effectively.
This patch removes require.async from nodejs.
1. It complicated the code unnecessarily.
2. Everyone uses sync require anyway.
3. It's got a lot of weird edge cases when mixed with sync require.
4. It is many months behind the commonjs spec anyhow.
