Update Readme

Draft to address #50 and #51 and a few sundries. Please perfect/cherry pick to your liking.

I decided that it made sense to handle #51 on the FAQ page but that #50 can likely be addressed satisfactorily by simplifying/clarifying the settings page (and possibly re-organizing it into subpages or tabs). On the latter, since you guys have added automatic API key pairing, we're nearing true one-click install experience (very nice!). In this light I'm thinking it makes sense to show the password settings by themselves, API settings by themselves, and share the love buttons by themselves.