This change verifies that manifests generated by Jinja2 do not contain
undefined data. If Spyglass attempts to generate a manifest file that
references undefined data, all previously created manifests will be
deleted and an error will be thrown. Users may bypass this function by
using the "--force" CLI option which will change all undefined data
errors to warnings instead.
Adds undefined data validation to Jinja2 manifest generation.
Adds "--force" option to bypass undefined data validation.
Adds tests for site_processor.py and enables tox testing/coverage.
Change-Id: Iff000eb173995156fbc6b44e621c59ba4dffae35
0d6eca47a1