Fog::Connection mixed in XML parsing via the `parser` argument which
wasn't much use for the majority of APIs using JSON.
This adds the deprecation warning and attempts to update providers to
the correct version of Connection that they need.
Either the cleaner `Fog::Core::Connection` or if reliant on the XML
parsing still `Fog::XML::SAXParserConnection`
The SAX parser will be moving to `fog/xml` fairly soon.
Since `fog-json` was extracted from `fog` it means if you rely on:
require "fog/provider/compute"
`Fog::JSON` was not defined although it was supposed to be a supported
use case.
This adds the requires for JSON or XML based APIs based on a quick scan
of each provider to declare the required part.
AWS seems to be relying on both. Which is nice.
Providers relying on native code dependencies
