TEIID-2422 adding workarounds to directly call source timestampdiff
functions
TEIID-2422 using calendar based timestampdiff by default
Conflicts:

	build/kits/jboss-as7/docs/teiid/teiid-releasenotes.html
	engine/src/main/java/org/teiid/query/QueryPlugin.java
	engine/src/main/resources/org/teiid/query/i18n.properties