Memory leak with BigNumber and toString()

The String class has long been a source of memory leaks and the problem is very well known. It is there only because somebody, at some point, thought that a char array was too difficult for a beginner to understand, but it really isn't. So, stay clear of this String thing, because everything you can do with it you can do without it. Once you have figured out how char arrays work, it's actually easier to use them instead of String, IMO.