Bug located in Edb.cutout()

[hui-zhou-a]

Description of the bug

`EDB API doesn't support multi threading well.

Steps To Reproduce

Do a cutout on a big board with num_of_thread =4. Then, define material thermal modifier.

[hui-zhou-a]

On linux, it reports segmentation fault.

Here is related discussion on stack overflow
https://stackoverflow.com/questions/10035541/what-causes-a-python-segmentation-fault

[svandenb-dev]

@hui-zhou-a can we close this issue ?

[hui-zhou-a]

@svandenb-dev No, the multi threading issue is not solved.