TravisCI: Run benchmarks and scenarios
TravisCI: Run benchmarks and scenarios

This patch changes the TravisCI script to run the `stack bench` target,
as well as a couple of scenarios using `reedsolomon-simple-bench`.

Whilst TravisCI is not a reliable benchmarking platform/system, the
results could give some indication/rough estimates of throughput
provided by the library.

NicolasT/reedsolomon,NicolasT/reedsolomon