Make infrastructure ready for Gateway interfaces

Hande route and nexthop add/delete from interface module for
InetInterfaces.
Make infrastructure ready for Gateway interfaces

Hande route and nexthop add/delete from interface module for
InetInterfaces.
Merge remote-tracking branch 'origin/master'

Conflicts:
	src/vnsw/agent/ksync/route_ksync.cc
Merge pull request #140 from praveenkv/master

Make infrastructure ready for Gateway interfaces