Address syntax errors in configuration + refactor (#255)

* Address a couple syntax errors in configuration

This change was primarily driven by the following syntax errors:

* enable_traces in Stackdriver needs to be enable_tracing
* jaeger receiver needs to be jaeger:

As part of this change, refactor and cleanup up readme a bit. Also
ensure consistent formatting in all sections.

* Further refactor

Make README more generic showing the most common options. Provide links
to additional information.

* Fix headers

* Few other edits to README

* Fix style issue

* Update architecture diagram

* Change ocagent to opencensus

* Add deployment models