Colors can be created

[TheoPannetier]

No description provided.

[richelbilderbeek]

Use branch issue_69.

There, make these tests come true:

void test_color()
{
    // #69: colors can be created
    {
      const color red = color::red;
      const color black = color::black;
      const color white = color::white;
      static_assert(red != black, "red is not black");
      static_assert(red != white, "red is not white");
    }
}

A static_assert is similar to an assert, except that the test happens during compiling (whatever that is :-) )