Converts the instance to a string.

This method exists for .NET compatibility. When using IronPython, the implicit string conversion that usually takes place in CPython will not kick-in, and in its place, IronPython will default to printing self.GetType().FullName or similar. Overriding the ToString method of .NET object class fixes that and makes Rhino/Grasshopper display proper string representations when the objects are printed or connected to a panel or other type of string output.