Issue #208: Allow relative paths to executor
The AppDefinition.executor property now has to hold a valid URI.
Add URI Annotation and validator.
Issue #165: Remove Content-Type from 204 responses
It is a jersey Bug: https://java.net/jira/browse/JERSEY-953
Should be fixed in Version 1.18.
Updated to latest 1.x version which is 1.18.1
The error remains the same.
Moved the class level annotation to every method and handle it explicitly.
jersey use transitive version of chaos
Use Try.isSuccess instead of map
URIValidatorTest:
  -add test for an absolute path of a relative URI
  -move empty String test to a separate case
AppDefinition: executor allows one of //cmd or path or <empty>
AppDefinitionTest: test executor field constraint
Remove URI validator, since it is not used any longer.
Merge pull request #219 from aquamatthias/master

Fix for Issue #165 and #208