printf not handling std::string correctly always

[tarterp]

Pull Request submitted to fix issue

colored message is printing garbled at times.

1>XPlotter.cpp(18): warning C4477: 'printf' : format string '%s' requires an argument of type 'char *', but variadic argument 1 has type 'std::string'
1>XPlotter.cpp(24): warning C4477: 'printf' : format string '%s' requires an argument of type 'char *', but variadic argument 1 has type 'std::string'

[Blagodarenko]

thank you!