[rfc][icedtea-web] following permissions attribute

[Jiri Vanek]

AIS

http://docs.oracle.com/javase/7/docs/technotes/guides/jweb/security/manifest.html#permissions

Please, any reviewer, read the specification. It appeared to be tricky to transform its spoken 
language to algorithm... Well at least default was specified without fog :(

Thanx for any comments!
   J.

not sure how with unittests, but reproducers are on the way...