Resolves Issue #11 and issue #5

[peter279k]

Changed log

• Resolves issue Green Button XML data validation error #11.
• Resolves issue Test enhancement #5.
• I also refer this sample Green Button data XML, and correct my sample XML.
• Using the DMD validation tool to validate this XML.
  These validating sections are as follows:
  • FB_1] Common
  • [FB_4] Interval Metering
  • [FB_5] Interval Electricity Metering

And the final validation result picture is as follows:

[peter279k]

The part of fix is about issue #5 and the issue #5 haven't accomplished yet.

The issue #11 has been resolved completely since this PR is merged.