Add warnings if the icon of a data source can't be set

Change signal/slot signature for data source

Modify construction of objects to use initializer list Add missing Tr

Merge pull request 140 from SCIQLOP-Initialisation feature/VisualizationWidget Widget of the tab widget are now of type VisualizationTabWidget

Widget of the tab widget are now of type VisualizationTabWidget Add addTabView and removeTabView lambda method connecter to their correspondant button in the VisuaizationWidget

Merge branch 'feature/PluginTreeItem' into develop

Adds vera exclusions

Loads SciQlop plugins

Connects data source widget to data source controller

Implements method to add a data source in the widget The method is a slot that will be connected with data source controller in the aim to create the data source representation in the widget when a new data source is set in the contoller