Adding i18n framework and localizing nav.

Adds the i18next module to implement internationalization.
Modifies the nav template and view to use localized forms of
the "Project" and "Task" terms.
Adds i18next as a new submodule.
Adds grunt-jsonlint as a dev dependency to validate larger and more
complex JSON files holding the translation strings.
Removed home and about page in require config.

Removed the references to the HHS-specific additions of a home
page and an about page.
Consolidated i18next configuration.

Configuration settings for the client-side instance of i18next
are now incoporated in the server-side configuration, too, so common
settings only need to be made in one place.
Added translation function calls to a couple of the server-side
controllers.
Removed unused translation strings from the translation files.
Added i18n config files to Makefile targets.

Added copying and restoring of the i18n configuration files
to the Makefile targets.
Removed duplicative lines in i18next hook.
Resolve express middleware error.

Removed setting custom middleware in the config/i18next.js file
that was conflicting with setting middleware in the config/auth.js
file. Middleware for i18next is set up in the before route in the
api/hooks/i18next/index.js file, instead.
Merge pull request #264 from katucker/devel-i18n

Add internationalization foundation