Separate tests and benchmarks

[lePereT]

ENHANCEMENT

At present there are some bits of benchmarking code that are present in the test suite. This is somewhat messy and leads to visual noise. As such it might be better to separate this code. There are two possible approaches:

1. Keep a single accompanying test file. However, this file returns a table with 2 functions, test() and bench(). The test suite could require each file and call its test method and the benchmark suite could do the same while calling the bench function instead
2. Create separate benchmarking files

This is quite low priority