function clamp( v, min, max ) {
	return addon( v, min, max );
}
Restricts a double-precision floating-point number to a specified range.

@private
@param {number} v - input value
@param {number} min - minimum value
@param {number} max - maximum value
@returns {number} value restricted to a specified range

@example
var v = clamp( 3.14, 0.0, 5.0 );
// returns 3.14

v = clamp( -3.14, 0.0, 5.0 );
// returns 0.0

v = clamp( 10.0, 0.0, 5.0 );
// returns 5.0

v = clamp( -0.0, 0.0, 5.0 );
// returns 0.0

v = clamp( 0.0, -0.0, 5.0 );
// returns 0.0

v = clamp( NaN, 0.0, 5.0 );
// returns NaN

v = clamp( 0.0, NaN, 5.0 );
// returns NaN

v = clamp( 3.14, 0.0, NaN );
// returns NaN