Update of the IPersistedFile interface to include functions, and stubs
added to the PersistantFileImpl
Merge branch 'master' of git@github.com:DawnScience/dawn-common.git

Conflicts:
	org.dawb.common.services/src/org/dawb/common/services/IPersistentFile.java
	org.dawnsci.persistence/src/org/dawnsci/persistence/internal/PersistentFileImpl.java

	All conflicts resolved.