HHH-465 - Support for NULLS FIRST/LAST

Conflicts:
	hibernate-core/src/main/java/org/hibernate/cfg/Settings.java
	hibernate-core/src/main/java/org/hibernate/criterion/Order.java

Conflicts:
	hibernate-core/src/main/java/org/hibernate/cfg/SettingsFactory.java
	hibernate-core/src/main/java/org/hibernate/criterion/Order.java