wget 1.16.1

This version bump also brings the --disable-pcre flag, and this commit makes that flag take effect unless you pass --with-pcre to the brew install.  Pcre is not a requirement, but wget opportunistically (and silently) links to it if it's on your machine, which can make for nasty surprises later.
An option with this text'll be automatically generated via the `=> :optional` syntax, so you can leave this line out.