Simplify iteration over INode children; make dependence on manhattan-style explicit

Issue 1117 crash on save project

transparent

2nd path is:
Open BA - Open Project - cancel - save project - crash

The crash fix is to always create a new project (done in method ProjectManager::newProject())

Furthermore NewProjectDialog distinguishes now between "create" and "save", since  otherwise it would look ugly on the UI. Imagine these steps:

Open BA, edit something, click "create new project". Now first a dialog for saving is shown, then a dialog for creating. Without the done changes, two dialogs with title "Create project" would show up.

Refactor output data read write

rm obsolete code; correct declare->define; rm 1-liner-braces; rm unnecessary else statements; precision hardcoded; static methods

Examples/Python: replace get_sample by exported version