see http://en.cppreference.com/w/cpp/language/operator_alternative

Just making this a bit more consistent throughout the code

The following is legal code in both C and C++:

  struct foo {
    struct bar { int a } x;
    int y;
  };

...however in C++ it defines a type called "foo::bar" instead of "bar".
Just avoid this construct altogether

Add Tests for String, Hash, Range and Symbol

Finish all Integer ISO Tests

don't close stdin.

Minor edits to test suite and Math module

Added some tests for Math module. Some refactoring in math.c; numeric tolerance exported as Math::TOLERANCE and also used for fuzzy tests in mrbtest suite