Basic color constants

constexpr inline rgb_color gBlack   = make_color(0,   0,   0,   255);
constexpr inline rgb_color gWhite   = make_color(255, 255, 255, 255);
constexpr inline rgb_color gSilver  = make_color(192, 192, 192, 255);
constexpr inline rgb_color gGray    = make_color(128, 128, 128, 255);
constexpr inline rgb_color gRed     = make_color(255, 0,   0,   255);
constexpr inline rgb_color gGreen   = make_color(0,   255, 0,   255);
constexpr inline rgb_color gBlue    = make_color(0,   0,   255, 255);
constexpr inline rgb_color gCyan    = make_color(0,   255, 255, 255);
constexpr inline rgb_color gMagenta = make_color(255, 0,   255, 255);
constexpr inline rgb_color gYellow  = make_color(255, 255, 0,   255);
constexpr inline rgb_color gOrange  = make_color(255, 165, 0,   255);
constexpr inline rgb_color gPurple  = make_color(128, 0,   128, 255);
constexpr inline rgb_color gMaroon  = make_color(128, 0,   0,   255);
constexpr inline rgb_color gNavy    = make_color(0,   0,   128, 255);
constexpr inline rgb_color gTeal    = make_color(128, 128, 0,   255);