#718 - Added required field validations for task plugin config properties
#718 - Renamed old curl plugin'd displayName to avoid confusion with new one. Added error field for additionalOptions
#718 - Handle empty json data for task plugin in create new task
#718 - empty errors hash in validation result is treated as success
#718 - TaskExtension reports appropriate error when a plugin is missing
#718 - Fixing issue during plugin preference load
Fix method name in agent
#718 - task plugin preferences are not loaded at agent side hence need to check for plugin availability through pluginManager
#718 - removing random logging calls I had added while testing
Merge pull request #760 from jyotisingh/json_based_plugins_bug_fixes

Json based plugins bug fixes