Add UTPP_SKIP_TESTS_AS_BUILD_STEP CMake option
Add UTPP_SKIP_TESTS_AS_BUILD_STEP CMake option

Helps address #104.

unittest-cpp/unittest-cpp,unittest-cpp/unittest-cpp,pjohnmeyer/unittest-cpp,grahamreeds/unittest-cpp,pjohnmeyer/unittest-cpp,unittest-cpp/unittest-cpp,grahamreeds/unittest-cpp,grahamreeds/unittest-cpp