Added `public` to func definitions

random(min,max) was returning an error (i.e. compiler didn’t recognize
it) until I made the method public. So, I made all the rest of the
methods public.
Adding asserts for min < max cases

min should always be less than max
Updating return value math

methods now calculate a value using .doubleValue() prior to casting
back to original generic type T
Deletions as per previous three commits