* "bro_is_terminating" is now "zeek_is_terminating"
* "bro_version" is now "zeek_version"
The old function names still exist for now, but are deprecated.
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