Modify manifest attributes for recent WebStart requirements

Versions of WebStart after java 1.7.0_51+(?) under at least some
circumstances require the "Permissions" attribute in the signed
jar file manifest
(https://blogs.oracle.com/java-platform-group/entry/new_security_requirements_for_rias)
This is now present in the jsamp.jar file (signed or not).
update history and acknowledgements xdocs