Automated testing system

[mnlevy1981]

Obviously some system is needed to ensure code on the master branch compiles and runs as expected... ideally with little or no human intervention.

Necessary Features:

1. Build executable with all compilers available on machine, report build errors
2. Run regression tests from reg_tests/ directory, report run errors
3. Compare output to baseline output, report answer changes

Some discussion has taken place on the developer's mailing list:

• Recommendation to avoid shell scripts as much as possible
• Look into CMake / CTest?

Besides needing to create this testing infrastructure, I think we need to completely overhaul reg_tests/ so that it will play nice with the test system and be more amenable to introducing new regression tests.