Blockfile Low level implementations of:
-->Chained Hashing
-->Extendible Hashing (https://en.wikipedia.org/wiki/Extendible_hashing)
-->External Sorting Algorithm (https://en.wikipedia.org/wiki/External_sorting).
Authors: Apostolos Florakis(https://github.com/apof) - Dimitrios Tsesmelis (https://github.com/JimTsesm)