todo

该文件为c++的数学函数库!是一个非常有用的编程工具.它含有各种数学函数,为科学计算、工程应用等程序编写提供方便！

* Add a higher level interface which accepts a 

start point, 
end point, 
result array (size N,  y0, y1, y2 ... ,y(N-1))
desired relative and absolute errors epsrel and epsabs

it should have its own workspace which is a wrapper around the
existing workspaces

* Implement other stepping methods from well-known packages such as
RKSUITE, etc