Cookbook normalize vector

[ggsmith842]

I added a recipe for the Normalize a Vector task in the Vector and Matrix Operations section. It uses the standard library and I provided an example of the usage.

Functions included:

• sum - to sum a list of squares.
• magnitude - calls the function Float.sqrt on the summed squares list to return the magnitude.
• normalize - calculates the unit vector by dividing each element of the vector, v by the magnitude.

[ggsmith842]

Thanks @cuihtlauac! I added your suggestions removing the odoc comments.