Translations:Release notes 0.15/39/en

FreeCAD's IFC importer has received a lot of work and testing, and a massive upgrade. The old, python-based importer, has been disabled (it is still usable from the python console, though), and FreeCAD now uses exclusively and intensively the newest, bleeding-edge version 5 (read more about it) of IfcOpenShell that is now available on all main platforms (be sure to download the version that matches the python version used by your FreeCAD installation). We now benefit from a much faster and reliable import and export, a much simpler and cleaner code (read: easier to extend), and already a few additional goodies, such as better support for curve-based objects and IFC properties.