Adding a resource provider for Generic Lists as JSON

In order to work with the Metadata Asset Editor's JSON Path option.
adding another null check
Merge pull request #327 from justinedelson/feature/generic-list-resource-provider

Adding a resource provider for Generic Lists as JSON
fixing package export version
[maven-release-plugin] prepare release acs-aem-commons-1.8.0
[maven-release-plugin] prepare for next development iteration