add missing std:: namespace qualifiers

When compiling the framework against ROOT 6, I noticed some compilation errors in IOPool/Streamer because "ifstream" was used, instead of "std::ifstream". I have no idea why this compiled before, because I can't find any relevant using directives or declarations.  So, this pull request adds any missing "std::" namespace qualifiers to instances of ifstream, vector, string, cout, endl, etc. that I could find in IOPool/Streamer.
In a couple of places, I also took multiple statements on the same line and put them on separate lines.