When passing invalid IPs or an out-of range port to parse_eftp()
a warning or error was generated on stderr (in addition to setting
the $valid field to F). Prevent the output by adding safe-guarding
and using IPAddr::ConvertString() instead.
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
