function nanmin( x, y ) {
	if ( isnan( x ) ) {
		return ( isnan( y ) ) ? NaN : y;
	}
	return ( isnan( y ) ) ? x : min( x, y );
}
Returns the minimum value, ignoring NaN.

@param {number} x - first number
@param {number} y - second number
@returns {number} minimum value

@example
var v = nanmin( 3.14, 4.2 );
// returns 3.14

@example
var v = nanmin( 4.14, NaN );
// returns 4.14

@example
var v = nanmin( NaN, NaN );
// returns NaN