Dev Structure Changes

These are per @MaxPower15 and @bschwartz recommendations:

* Change Embed API doc to "How to Construct an Embed Code"
* Change Player API to "Javascript Player API"
* Make Embed Options a top-level link (both DevHQ and Index)
* Merge Customize API into Data API
* Get Javascript Events on top-level Index Page
* Change Player API 'Examples' to 'Tutorials'
* Clean up DevHQ page

:question: 
* should Upload API and Stats API get merged into Data API as well? 
* Is Data API the right name?