Bahtinov mask generator (modded)

This is a remix of BrentB's Bahtinov mask generator, thing: 160391.

• Handle(s) height is now customizable
• If the center hole diameter is 0 then 2 more handles will be added to model for safer fit
• The handle(s) position relates to the width of OTA

Regarding to my work we sell masks for different telescope types, so I made this slight modifications for a better general usability.

Thanks to BrentB for the original code :)