Update Pivot to New security requirements for RIAs in 7u51

As seen here ( https://blogs.oracle.com/java-platform-group/entry/new_security_requirements_for_rias ), we have to update our jars or users won't be able to run our Tutorials/Demos from the Web Site ... and even when running from related war files in our distribution.

Note that for signed jars we have only a self-signed certificate, so we have to check with ASF if it's something that could be handled at Infra level (from a Build Server, or something that takes released jars and sign them ...). Note that the same apply even with pack200 version of our jars.
Maybe a related issue for INFRA could be useful ...

Some discussions here:
http://apache-pivot-developers.417237.n3.nabble.com/Update-Pivot-to-New-security-requirements-for-RIAs-in-7u51-td4026251.html