Add performance benchmarks

As we make changes to the library and add new capability, it would be useful to have a way to benchmark performance on key parts of the library so that we could see before and after a change.

Possible functions to benchmark
- functions for parsing flux results
- functions for interpolating lines on a graph
- what else?

Start by locating the library functions that parse Flux results and interpolate lines on a graph. Define which key functions to benchmark, how results will be compared before and after changes, and what benchmark output demonstrates that the work is complete.

Written by the indexing model from the issue text.