Use GNU time in update-counts.sh script.
Update to update-counts.sh script.

Consolidate timing of benchmark programs by simulating a do-while
loop in Bash.
Update to update-counts.sh script.

Report when benchmark program terminates with an error.
Update hamlet.sml benchmark program.

Close the input file after each loop to avoid "SysErr: Too many open
files".
Update fft.sml benchmark program.

The 'test' function raises "Subscript" with a non-power-of-2 argument.
Update model-elimination.sml benchmark program.

Iterate 'main ()' according to 'doit' size parameter.
Update benchmark iteration counts.

Increase the benchmark iteration counts so that all benchmarks run for
at least 30 seconds (for amd64-linux on an "Intel(R) Core(TM) i5-3570K
CPU @ 3.40GHz").
Ignore uniquely named benchmark files.
Merge pull request #75 from MatthewFluet/benchmark-infrastructure

More updates to benchmark infrastructure.

Highlights:
 * Make `update-counts.sh` script more robust.
 * Update `hamlet.sml` benchmark program to close input file after each loop.
 * Update `fft.sml` benchmark program to only invoke `test` function with power-of-2 arguments.
 * Update `model-elimination.sml` benchmark program to iterate `main ()` according to `doit` size parameter.