Updated test data and changed data location
Change placeholder value from -9 to 0 in Plink .fam output
Allow user to configure representation of missing data in Plink .fam output
Merge pull request #14 from iainrb/devel

Updated test data and Plink .fam output
Merge pull request #15 from wtsi-npg/devel

Additional changes for release 0.4.4