o add functionality to interpolate <extend/> element.
o add functionality to interpolate <extend/> element.


git-svn-id: 2c527eb49caa05e19d6b2be874bf74fa9d7ea670@162562 13f79535-47bb-0310-9956-ffa450edef68

olamy/maven,cstamas/maven,olamy/maven,skitt/maven,rogerchina/maven,mizdebsk/maven,stephenc/maven,likaiwalkman/maven,olamy/maven,rogerchina/maven,ChristianSchulte/maven,aheritier/maven,mcculls/maven,runepeter/maven-deploy-plugin-2.8.1,dsyer/maven,xasx/maven,likaiwalkman/maven,cstamas/maven,Mounika-Chirukuri/maven,pkozelka/maven,wangyuesong0/maven,barthel/maven,njuneau/maven,trajano/maven,xasx/maven,aheritier/maven,wangyuesong/maven,cstamas/maven,karthikjaps/maven,changbai1980/maven,stephenc/maven,pkozelka/maven,Distrotech/maven,wangyuesong/maven,atanasenko/maven,trajano/maven,skitt/maven,xasx/maven,mizdebsk/maven,njuneau/maven,changbai1980/maven,karthikjaps/maven,skitt/maven,Tibor17/maven,atanasenko/maven,wangyuesong0/maven,lbndev/maven,vedmishr/demo1,stephenc/maven,kidaa/maven-1,lbndev/maven,josephw/maven,changbai1980/maven,pkozelka/maven,keith-turner/maven,wangyuesong0/maven,barthel/maven,gorcz/maven,atanasenko/maven,wangyuesong/maven,vedmishr/demo1,dsyer/maven,rogerchina/maven,mcculls/maven,ChristianSchulte/maven,gorcz/maven,lbndev/maven,dsyer/maven,trajano/maven,vedmishr/demo1,Distrotech/maven,likaiwalkman/maven,barthel/maven,mcculls/maven,gorcz/maven,apache/maven,Tibor17/maven,keith-turner/maven,kidaa/maven-1,keith-turner/maven,josephw/maven,apache/maven,runepeter/maven-deploy-plugin-2.8.1,apache/maven,aheritier/maven,josephw/maven,kidaa/maven-1,njuneau/maven,karthikjaps/maven,mizdebsk/maven,Mounika-Chirukuri/maven,ChristianSchulte/maven,Mounika-Chirukuri/maven