This allows to feed any data directly into the sexpr parser. This can be
used for:
* Benchmarking, profiling and optimisation
* Fuzz testing
* Debugging
As an example, it demonstrates that a 15MB kicad PCB file (the CIAA
motherboard project) takes 1.5s to parse, and uses 140MB of heap
allocation within the Parse() method (using Valgrind massif).
John Beard