The framework so far populated data structures with missing fields
even when those fields are defined without the &optional
attribute. When using the attribute, such entries continue to get
populated.
Update tests to reflect focus on unset fields.
This also installs symlinks from "zeek" and "bro-config" to a wrapper
script that prints a deprecation warning.
The btests pass, but this is still WIP. broctl renaming is still
missing.
#239
