Rewrite DSHttpAdapter page on js-data.io

[jmdobry]

Need to remove api reference docs because that will be auto-generated by the jsdoc comments in the source code. The new js-data-http should be just guide, usage, & examples documentation.

• - Document custom deserialization
• - Document using window.fetch
• - Document using the adapter's lifecycle hooks

[jmdobry]

Done.

[jmdobry]

Okay, maybe not all the way done.