Implement azkaban project validation plugin.
Refactor DirectoryFlowLoader to become the default project validator.
Fix the comments received in the pull request (#326).
Change the <item> tag inside the validator xml configuration file to <property>.
Change the way test cases deal with expected Exceptions to make the code cleaner.
Remove SuppressWarnings Annotations in the test case.
Change the name and comment of the method that fetches the name of a ProjectValidator to make them more accurate.
Update the test jar file so that the TestValidator class implments the updated version of the interface ProjectValidator.
Update the test validator xml configuration file and the XmlValidatorManager comment to use property instead of item as the tag for key/value pairs passed to validators.
Merge pull request #326 from Victsm/validator-plugin

Validator plugin