Dynamic workers toggle. Separate stats toggles. README and FAQs

  * Created separate toggles for output-http-stats and output-tcp-stats
  * Created HTTPWorkers option (defaults to 10) to allow larger number of HTTPWorkers to be spawned.
  * Refactored output_http to allow dynamic http worker scaling when httpworkers equals -1
  * Updated README.me to include updates and some common FAQs.