Add methods to UIFormWidget for saving and restoring widget states

[lauramurgatroyd]

Closes #61

• Adds the following new methods to UIFormWidget, FormWidget, FormDialog and FormDockWidget:

  • saveAllWidgetStates - Saves the state of all widgets in the form. This can be used to restore the state of the widgets using the restoreAllSavedWidgetStates method.

  • restoreAllSavedWidgetStates - Restores the state of all widgets in the form to the state saved by the saveAllWidgetStates method. If the saveAllWidgetStates method has not been called, this method will do nothing.

  • getAllWidgetStates - Returns a dictionary of the state of all widgets in the form.

  • getWidgetState - Returns the state of the widget.

  • applyWidgetState - Applies the given state to the widget with the given name.

  • applyWidgetStates - Applies the given state to the widgets in the form given by the keys of the state dictionary.

• Adds an example of a FormDialog: dialog_save_state_example.py where all of the widgets are saved and restored if you press "Ok", whereas the previous values of the dialog are restored if you press "Cancel".

• Adds unit tests to fully cover all of the new methods

• setup.py:

  • Always normalise the version from git describe to pep440 - this is required due to: When conda building, get "Built wheel for ccpi-viewer is invalid" error CILViewer#333

[paskino]

Some docstrings to be updated.

Why should we keep the default of role set to None?

I don't understand why the default widget name is name.

[lauramurgatroyd]

I have updated the docstrings as you suggested