Add changes for setting last_updated on Session instead of Subject
Removed call to lastupdated_subj2sess since we now have a separate
script
Set last_updated using specific datatype xml path
Have to use specific datatype when querying last_modified to get the
most current value
Fix type in function name
Fix bug in list_sessions for multiple types of sessions
Change print statements in lastupdated_subj2sess
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Merge pull request #19 from VUIIS/session_last_updated

Add changes for setting last_updated on Session instead of Subject