Added file_io module and updated README to reflect addition.

This additional module has functions for reading and writing delimited files to and from 2D lists where first dimension is rows and the second is columns. It also contains a function for formatting output text for a file format called <a href='http://www.1000genomes.org/wiki/Analysis/Variant%20Call%20Format/vcf-variant-call-format-version-41'>VCF<\a> from a 2D list. This format is one of the current standard file formats within genomics, and is required for input to third-party tools used in this project and many others in the lab.