Merge `ajax/key-concepts` and `ajax/jquery-ajax-methods` into a more narrative Getting Started

In addition to addressing @addyosmani's points below, I think ultimately these two pages belong as a single unit, with much less re-documentation of APIs

http://stage.learn.jquery.com/ajax/key-concepts/

• Where are all the examples? $.get()? $.post()? etc. A lot of methods are mentioned but as a beginner I would hope to see examples too. This is where we need to either move over examples currently in the API docs or form a bridge between both resources.
• I would expect/hope to see tutorials here - either in a separate entry or in key concepts. Based on what we have, a reader would appreciate that $.ajax() does a lot, but I think this is where we should be educating them further.
• Consider covering typical tasks (some of which the API docs do): how do I consume a JSON data feed from an external/local source? worth showing a twitter API example? xml for those still using it?
• We currently don't have a mention of deferreds at all. 6 months ago I would have said it's considered a more advanced topic, but given just how much power it has to improve the way people approach XHR, should this also be covered here? -- YES.
• JSON is a "key concept" but probably should be its own article

http://stage.learn.jquery.com/ajax/jquery-ajax-methods/

• Again we have nowhere near enough examples. We mention lots of options - perhaps it would be useful going through how to use them?. Don't have to cover everything but give people some snippets to help them 'grok' how it all fits together
• I think we need to decide how much we rely on the API docs site for our examples. Right now we're trying to push people to look there for examples and narrative (via links), but I think the docs site should cover a) how to use methods, b) gotchas with perhaps some more of the narrative being in the learning site. Thoughts?