8004371: (props) Properties.loadFromXML needs small footprint XML parser as fallback when JAXP is not present

[Alan Bateman]

Joe sent me an update with changes to address issues discussed so far, 
I've put the webrev here:

http://cr.openjdk.java.net/~alanb/8004371/webrev.02/

Joe - the classes you sent me were in different packages, also the 
formatting was a bit messed up in several classes, I've fixed up those 
issues so you may need to re-base from the patch file included in the 
webrev.

-Alan.