The previous excel spec seemed to lack a consistent structure. This
change redesigns the spec to more simply and generically find where data
is located in the spreadsheet.
Change-Id: I98c1553531897e8c623caa8a1b9334ea915a3f49
Adds tests for the Excel plugin's parser and extractor.
Enables pep8 and fmt checks on the tests directory.
Increases plugin test coverage to 94%, sets new minimum to 92%.
Fixes DNS and NTP server extraction with regex.
Updates file licenses.
Change-Id: I35ee97574e6d63b7a82cfa94caf79db5db9755e7