DynArray : add a new interface - support different element size

Implement in file DynArray/general_func.c, the interface is in
DynArray/general_func.h.

*WARNING*
	This function can only support up to 4-dimensional array
	point. When I want to get a pointer to 5-dimensional array,
	the program crashed and I get a "segment fault".

I haven't find out why it can not support more than 5 dimensional array.
Merge branch 'master' of https://github.com/bngit/CodePractice