Add FlowScene::allNodes() paceholder#229

Add signal for embedded widget size changes (paceholder#187)

Update Qt versions for appveyor

Remove NodeDataModel::clone() (paceholder#164)

* removed NodeDataModel::clone(), using a more classic Factory/Builder pattern.

* trying to make visual studio happy

* Allow the DataModelRegistry to use static method Name() if defined

* use modern type_traits

Fix memory leake by passing parent to FlowScene (paceholder#151) (pac…

…eholder#155)

Export NodeState from dll (paceholder#156)

Implement Converters separately from DataModels (paceholder#148)

Fix osx build on travis

Version 1.0.0 alpha