Clarify directly instrumention vs merely exposing. (#749)
Clarify directly instrumention vs merely exposing. (#749)

Directly instrumented applications use a Prometheus client library that
follows our guidelines, and can be used as examples of software doing
that.

Recategorise things accordingly, updating links as needed and
adding some more I know of.
I'm taking Quobyte's word for it that they're directly instrumented,
as it's commercial software and thus I can't check.
kubernetes-mesos has no instrumentation that I can find.
chosenken/docs,ddfreyne/prometheus-docs,prometheus/docs,prometheus/docs,prometheus/docs,du2016/prometheus-docs,du2016/prometheus-docs,chosenken/docs,chosenken/docs,ddfreyne/prometheus-docs,du2016/prometheus-docs,chosenken/docs,ddfreyne/prometheus-docs,ddfreyne/prometheus-docs