Scriptcwl

Added

* Allow addition of default values to workflow inputs (32)
* List of steps and workflows in steps library is ordered alphabetically

Added

* Python 3 compatibility (and testing with [tox](https://tox.readthedocs.io/en/latest/))

Added

* Generate unique names for steps that are added to the workflow more than once (31)
* Pass all outputs from a step, instead of just one (27)
* Improve listing of workflow steps

Added

* Load ExpressionTools as steps

Changed

* Preserve the order in which steps were added to the workflow

Changed

* Replace pyyaml by ruamel (fixes compatibility with cwltool)

Added

* Documentation for WorkflowGenerator and Step (15).
* Allow step to be scattered (17)
* Tests (9)
* Shebang to saved CWL file (14)
* Preprocess shortcuts in CWL steps (12)
* Allow workflows to be used as steps (subworkflows) (4)
* Take into account optional arguments (6)

Removed

* Step.get_input() because it was not used (21)