Much more cleanup on the performance testing infrastructure:
- Added new abtract Results class to keep CoreFoundation out of the tests. There are many subclasses for different settings:
    Results::Result::Dictionary
    Results::Result::Array
    Results::Result::Unsigned
    Results::Result::Double
    Results::Result::String
- Gauge<T> can now write themselves out via a templatized write to results function:
    template <class T>
    Results::ResultSP GetResult (const char *description, T value);

- There are four specializations of this so far:
    template <>
    Results::ResultSP GetResult (const char *description, double value);

    template <>
    Results::ResultSP GetResult (const char *description, uint64_t value);

    template <>
    Results::ResultSP GetResult (const char *description, std::string value);

    template <>
    Results::ResultSP GetResult (const char *description, MemoryStats value);
- Don't emit the virtual memory reading from the task info call as it really doesn't mean much as it includes way too much (shared cache + other stuff we don't have control over)
- Fixed other test cases to build correctly and use the new classes