Implemented segmented sieve.
Implemented segmented sieve.

Originally had segment size at 100, which took around 15min to generate 1x10^6 primes however, I observed that changing the segment size to 1000 and then to 10000 reduced the waiting times to 1.5min and 9.5sec respectivley.
A-Mckinlay/Generating-Primes,A-Mckinlay/Generating-Primes