DeepState Test Integration

[ex0dus-0x]

This pull request integrates efforts to convert the pre-existing test suite in setup-tools over to Trail of Bits' DeepState framework in order to enable exhaustive unit testing with fuzzing. In addition to the actual tests, coverage measurement support is also integrated with the build system using gcov.

Few notes:

• DeepState, unlike GoogleTest, does not currently supported DISABLED_* tests or filtered test selection during runs (ie no running test with specific patterns), but only either a single test (with --input_which_test) or all.

• There is a new option in CMakeLists.txt for compiling with the -D_GLIBCXX_USE_CXX11_ABI flag, and was used prior when encountering incompatibilities with older GCC ABI versions.