[Issue] Document containing an IfcProject and FreeCAD objects

[balrobs]

Steps to reproduce:

1. Start FreeCAD
2. File->Open IfcProject_01.ifc.txt (with Native (ifc_import))
3. Select BIM workbench
4. Notice Lock-Status is ON
5. Save file as IfcProject_01.FCStd
6. Notice Lock-Status is OFF
7. Draw line with line command
8. When I click for the line end point I see this in the Report view
   
9. And when I click on the Close-Button to terminate the line command I see this in the Report View
   
10. Then FreeCAD crashes

[yorikvanhavre]

There are two problems here:

1. the lock button doesn't stay on after reloading
2. creating a line in locked mode fails

[yorikvanhavre]

Problem 1 should be solved by the above commit.

For problem 2, 2D entities are not working well yet, but at least it should be better handled.

[balrobs]

After an update here on my site problem 1 unfortunately still remains. I am follwing the mentioned steps.