Code coverage

[mikebentley15]

Now that there is a testing framework, only a meager amount of the framework is actually tested. I would like to instill a code coverage metric. If gcc is used, then we can use gcov/lcov. If clang is used, then we can use the -coverage flag provided by clang. Ultimately, we need some metric to know how much of the code is tested and how much is untested.

At least for now we have a test framework, and new pull requests will be required to test the functionality that is added or modified.