Method distance

jni/venus/vec4.h:119–123

	}

	friend T distance(const vec4<T>& pt1, const vec4<T>& pt2)
	{
		vec4<T> v = pt2 - pt1;
		return v.length();
	}

	friend T dot(const vec4<T>& v1, const vec4<T>& v2)
	{