[foreign] RFR 8217453: add support for member annotation scheme

[Maurizio Cimadamore]

Hi,
this patch implements the member-based annotation scheme described here:

http://cr.openjdk.java.net/~mcimadamore/panama/panama-annos.html

(see end of document)

This patch diverges from the proposal in two minor aspects:

* @NativeCallback is left in place (we have bigger plans for allowing 
callback types to be referenced by name)
* unresolved layout grammar: the layout expression used braces - e.g. 
${foo}, not $(foo), to minimize confusion with layout annotations

I've also took care of a couple of minor issues:

* I added exclusion for the SystemHeadersTest which fails on Windows if 
Visual Studio is not installed
* I fixed a bunch of javadoc issues (esp. in Pointer) which prevented 
javadoc to be generated correctly

Webrev:

http://cr.openjdk.java.net/~mcimadamore/panama/8217453/

Thanks
Maurizio