cad/netgen-lvs: Update 1.5.300 => 1.5.305

Changelogs:

• http://opencircuitdesign.com/netgen/history.html
• https://github.com/RTimothyEdwards/netgen/compare/1.5.300...1.5.305

• Use standard SHEBANG_FILES instead of custom post-patch

Approved by: yuri@ (maintainer, Mentor)
Differential Revision: https://reviews.freebsd.org/D53583