Use correct Root6 type names

Fix for fatal exception in relvals due to change in normalized type names from ROOT 5 to ROOT 6.
ROOT6 uses Long64_t, ULong64_t, and std::string for what were, in ROOT5 long long, unsigned long long, and std::basic_string<char> respectively.

With this fix, the relvals now fail later in their execution due to an unrelated exception.  That now needs to be fixed.