parameterized absolute_accuracy_tolerance

[jp7745]

currenctly absolute_accuracy_threshold is fixed at 0.001 Hartree in each problem instance. Consider expanding to 0.0016 Hartree (1.6 mHa) to be consistent with chemical accuracy or otherwise expose this parameter so it can be modified when generating results.

[jp7745]

probably changing accuracy to 0.00159362 for all problem instances. (This is 1 kCal/mol converted to Hartree.)

[jp7745]

PR #154 set accuracy to ~1.6mHa for all problem instances.

future work will expose that tolerance as an argument for more analysis.