Looks like constcast repo has fallen off the internet :
fatal: remote error: access denied or repository not exported: /a/nw/ad/0c/93/1421452/254611723.wiki.git
fatal: clone of 'git://github.com/constcast/vermont.wiki.git' into submodule path '/Users/Nick/Software/vermont/docs/wiki' failed
Probably best to use tumi8 as that's the definitive uptream anyway.