This removes most of the legacy upstream config madness by not using
weird config files spread all over the place.
This isn't the solution to other config reading fragility issues, but
it does move the whole config back to the central airtime.conf file.
Also fixes them elsewhere, apart from having switched to a vendorized version, I also used one that is already namespaced.
The easy way out here is to use it in the namespaced fashion, it is only used in a few places and I know the library well enough to be certain that nothing much changed apart from the namespacing.
Robb Ebright
Lucas Bickel
Duncan Sommerville