Do not attach the Start Page to an existing document as otherwise weird behaviour can be observed:
1. Start FreeCAD
2. Open a project file or data file
3. Open the Start Page
4. Make a change to the document
5. Close the document. You won't be asked to save your change
6. In the tree view the document is still shown because the Start Page is attached to the document
7. Close the Start Page. Now you will be asked to save your change
On systems with legacy monitors the display might be not as large as needed to display completely the start page. In that case the user is forced to use the keyboard to scroll horizontally the start page.
* Set parent object to FileCardDelegate so that it will be destroyed if the list view is destroyed
* Inside FileCardDelegate::paint() delete the widget
Start: Automatically run command when event loop starts
Also sets PartDesign as the default startup Workbench.
Start: Add checkbox for starting or not starting Start
Start: Correct default card size parameter access
Start: General cleanup
