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
Also removed RefExpr::Eval(Val*) method since it was never called
(Clang emitted warning about this hiding overloaded virtual function
UnaryExpr::Eval(Frame*)) and doesn't appear to be necessary even if it
was called to avoid the default vector handling of UnaryExpr::Eval
(as the comment suggests as the intention).
