Added an extremely minimal ‘irb’ implementation. Next step is to properly display return values.
Fixed MrbValue to have a (quite decent actually!) ToString() implementation. It gets quite simple since we can just call to_s on the underlying Ruby object…
Clear the most recent exception after reading it out, since that’s a quite crucial part of how the exception handling works with MRuby.
Added a simple little header so people get a better idea of how the program works.