The gem is available at github: https://github.com/ged/linkparser
It is much easier (at least for me) to install the required C libraries (they are part of AbiWord) than Enju parser.
Yup, that would be a great feature to add, although I'm currently focusing on solidifying the core libraries before starting to work on new stuff. Are you interested in working on a wrapper? You could use /lib/treat/workers/processors/parsers/stanford.rb as an example.
We've got @jbnunn working on this one currently.