forked from Mirror/wren
- Primitives can now signal an error. - An error prints a callstack and ends the current (and right now only) fiber. - Arithmetic operators error if the operand is not a number. - Real error for method not found. - Associate source file name, and method names with functions. - Debug line number info for functions. Unfortunately, this regresses perf on fib about 15%, mostly because of the better checking in arithmetic ops. There's still a bunch of clean up to do, but this is a big step in the right direction.