scaffolding tests
First passing test that ensures the manifest parser throws appropriate error when bad manifest JSON is passed to it
More passing tests for throwing suitable errors for bad input
Manifest parser returns combined manifest definitions
Changing existing code to actually live in a manifest validator object

With plans to extend that validation logic
THrowing an error when asset definition in manifest JSON is not an object
Validating asset paths/URLs
Removing unintentionally committed test files
Validating asset type
Validating before and after asset definition elements