Benchmark framework now caches interpreter results.

Most time in benchmarking was spent on rerunning the interpreter on the
same examples with the same result. The se results are now cached and
reused.

The result are saved in MeasurementsInterpreted.value
===> do not commit this file, since it contains machine-specific
measurements! <===

When you remove this file, all measurements are computed from scratch.
Merge branch 'master' of https://github.com/cwi-swat/rascal.git