Improvments to accessing insurance details

You can now get the group number and plan number out of the response with relative ease. The member number is also easier to get (as id) for the patient.

Tracing and Repeatbility

• The response from the DoInquiry eligiblity check now captures the raw XML and
  can be recreated from stored XML.

• Traces are available as part of the DoInquiry eligibility response. Trizetto
  adds a trace_id ("99Trizetto") and a trace_number to each request that can be
  provided to them later as part of a support request. The payer may also add
  a trace which is available also.

Its Alive

• Make it simple to answer the question: does this person have insurance
  coverage via the WebService Eligibility check. The raw XML response is parsed
  into plain old ruby objects.
• Added tests (woo hoo)
• Readme update with examples
• Documented the WebService Eligibility check
• Requirement minimum version of ruby is 2.3