Some refinements to the script. 1. No need to invoke the script from the benchmark directory. 2. The timing information is also logged into a file. 3. Script can be completely quit with a single Ctrl-C. 4. Benchmark output redirected to /dev/null to avoid cluttering stdout.    (This should be changed so the output can be optionally logged.) 5. Using the subprocess module to run the benchmarks. 6. Some minor formatting fixes.
Some refinements to the script.
1. No need to invoke the script from the benchmark directory.
2. The timing information is also logged into a file.
3. Script can be completely quit with a single Ctrl-C.
4. Benchmark output redirected to /dev/null to avoid cluttering stdout.
   (This should be changed so the output can be optionally logged.)
5. Using the subprocess module to run the benchmarks.
6. Some minor formatting fixes.

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