Read the memcpy results in json and print out the results in tabular
form, in addition to generating a graph of the results to compare all
of the implementations.
The format of the output is extensible enough to allow this kind of
analysis to be done on other string functions as well.
* benchtests/scripts/benchout_strings.schema.json: New file.
* benchtests/scripts/compare_strings.py: New file.
