Before, we used a local setjmp/longjmp for error handling.
Using janet_panic means errors can be more easily expressive and
code can be smaller.
However, we still need to make vector memory get gc collected, as
panics can cause the runtime to skip janet_v_frees.
A consistent style should help with contributors and
readability. We use astyle as the formatter as can make a pretty
good approximation of the current style and my preferred style.
Astyle can be found at http://astyle.sourceforge.net/astyle.html
