assert_panic_free

A lightweight higher-order-function that doesn't compile
if a function you pass to it might panic. This probably
wont' work unless you're compiling your code with optimizations
enabled.

Example

works when built with optimizations / release:

assert_panic_free::assert_panic_free(|| 32);

doesn't work:

assert_panic_free(|| panic!(":("));

Inspired by no_panic and panic_never but I wanted something that allowed for fine-grained panic reduction (like no_panic) but also something that compiled fast (like panic_never).