Merge pull request #14 from wtsi-npg/master

Merge changes for release 0.7.3
Merge pull request #15 from wtsi-npg/master

Merge in release 0.7.4
Merge pull request #17 from wtsi-npg/devel

Devel
Merge pull request #18 from wtsi-npg/master

Merge in release 0.7.5