Benchmarking + Optimisation

[makspll]

The crate is very new, and I am not that familiar with Rust + Bevy,

Baseline benchmarks should be written, and code optimised.

A good start would be, not running scripts which do not have any callbacks corresponding to the set of events fired this frame.

[makspll]

For benchmarks I'd like to see:

• Comparable native bevy calls on world vs doing so from script one liners
• break down of time consumed by safety mechanisms when accessing something via reflection

[makspll]

#232 is part of the initial work towards this

[makspll]

Closing in favor of #278