Function to generate OVSF code

Function to generate OVSF code. Read file for usage details or refer description.

This function generates OVSF code (Orthogonal Variable SPreading Factor)
Usage:

x = ovsf(y,z)
x, the output cell array having required OVSF codes
y, number of codes required
z, array having length of each code to the base 2 i.e. 2.^2 = 4
example y = 3 z = [4 2 3]
this will give a cell array with [1x4] [1x8] [1x16]
length = 2.^n , enter n in length of array
The code is not optimized yet, user is free to optimize
do not forget to leave a comment

This is version 1 of the file, and it need optimization. More details of OVSF code can be found on wirelesscafe.wordpress.com