introduced language-based categorization, starting with labels

the assumption here is that most users are interested in one particular
language (rather than an overview based on the underlying data model)

while the top provides a brief summary (using the selected locale),
these language sections provide a detailed overview (with non-localized
values)
added support for notes

NB: note annotations are currently being ignored
added support for note annotations

not pretty (cf. inline comments), but sufficient for the moment
improved notes styling

unfortunately, the Bootstrap grid induces yet more divitis here