Transfer metadata by copy / upload / download of zip files, unify copy
of streams, copy metadata during copy of courses, remove backwards
compatibility mode for import

Move the functions of OlatRootFile and OlatRootFolder to the Local
implementations to simplify the use of VFS, implements factory methods
in VFSManager, reduce the number of call to meta informations in folder
listing

OO-848: extended postCopy() method with source and target Course to get the copy of a whole course working

OO-848: enhance the interface of course nodes to do a post copy processing different from the import one

OO-170: refactoring of the property table, move efficiency statements and initial/recent launch dates to their own table

--HG--
branch : bps