Compile the list of public API provided by NVBench library  #355

Regarding #1, we should review the list of symbols we intend to be public, export them (i.e., add __declspec(dllexport) annotation for MSVC) and hide the rest (i.e. add __attribute__((visibility("hidden"))) for GCC/Clang).

Incidentally, doing this review would unblock #323

Originally posted by @oleksandr-pavlyk in #354 (comment)