Added header comment to main file and changed the default size
to the largest effective size (as the methods are currently written)
Removed defunct enum (Type)
Altered mean and stdTwoPass methods to handle very large lists
I did not find a way to make the stdOnePass method work, so it just
informs the user that it cannot calculate it accuratly and returns 0

I also added exception handling for the array allocation
Added more memory and file related error handling
Found and fixed several file reading bugs that occured with large number
sets.
Finished fixing functions to deal with large sets.
Added basic unit tests for mean and the std functions