Samplesheets now handle dual indexes
Use immutable object style

which allows object creator to set attribute requiring the dual index
split, and have this attribute specify the size of the dual indexes
Merge pull request #3 from dkj/dual_index

Dual index - Use immutable object style
pulled changes from remote jenniferliddle/dual_index; resolved conflicts, fixed failing test
Merge pull request #176 from wtsi-npg/devel

pull request from wtsi devel to master to create release 77.3
Merge pull request #177 from wtsi-npg/master

pull wtsi master (release 77.3) to wtsi devel
Merge pull request #3 from wtsi-npg/devel

merge changes from wtsi-npg