Gemfile: update ffi dependency to 1.9.5

Apparently, ffi 1.9.4 has disappeared:

    bundler
    Fetching gem metadata from https://rubygems.org/.........
    Could not find ffi-1.9.4 in any of the sources

So updating the dependency to 1.9.5
DevelopersDoc: rendered MD: prevent html_escaping

Mitigate the undesired impact of
687c672f2eaee4b1c5a43512df4b4fdb0c0e170f
and prevent HTML escaping on the field displaying the developers
documentation rendered from MarkDown into HTML.
Views: fix typo in registration/complete.erb
Merge pull request #15 from University-of-Auckland/develop-misc-fixes

RapidConnect: misc fixes (html escaping, typo, dependency)