suppress empty field identical
even more succinct missing svg task output

don't list the affected classes, but the missing files
Use files into the main filesinstead of including

This is better for caching. Configuration options must live in
common/conf.scad, as this is still included, so the variables defined
there are propagated to the main namespace.
Revert "Use files into the main filesinstead of including"

This reverts commit e570ca462278dc3608ed1b74eb957fb9364a1e08.
a few additional properties in Specification page