Airgap mesh creation with user defined fsl files for stator and rotor

[sasrigais]

This fixes an issue with mesh-airgap.mako and user defined fsl files for both stator an rotor models. The actual implementation had several flaws:

• variables agndst and alfa where condsidered not nil, which is not always the case
• mixed up radians and degrees in polar to cartesian conversion
• missed creating some nodechains

Also it was not considered if the user had already created the airgap mesh within his fsl-files. If so, he could now set the variable airgap_created to true, when he does the creation.

I hope this is useful to other users too.

Keep up the great work with femagtools, they are awesome :)

[ronaldtanner]

Do you have a simple test case for this?

[sasrigais]

Hi! I will setup an example and send it to you by e-mail (company internal models)

[ronaldtanner]

thanks.