Property modernization w/ Gaudi v28 (StoreGate-03-09-00)

	* updates for Property modernization. see gaudi/Gaudi!182
	* updates for DataHandle::setKey being const
	* requires Gaudi v28
	* tag StoreGate-03-09-00

M       test/VarHandleKeyProperty_test.cxx
M       test/VarHandleProperty_test.cxx
M       src/VarHandleKeyArrayProperty.cxx
M       src/VarHandleKeyProperty.cxx
M       src/VarHandleKey.cxx
M       StoreGate/VarHandleProperty.h
M       StoreGate/VarHandleKey.h
M       StoreGate/VarHandleKeyArrayProperty.h
M       StoreGate/VarHandleKeyProperty.h

2016-12-13  scott snyder  <snyder@bnl.gov>

	* Tagging StoreGate-03-08-05.
	* src/SGImplSvc.cxx (recordObject): Do not return an invalid
	proxy.
...
(Long ChangeLog diff - truncated)