(libT) #1220 'change file and folder names': add a test to confirm passing tor->info.name as the 'oldname' argument works

git-svn-id: svn://svn.transmissionbt.com/Transmission/trunk@13835 f4695dd4-2c0a-0410-b89c-da849a56a58e
(libT) #1220 'change file and folder names': add unit tests for renaming a root, then branch, then leaf in the torrent

git-svn-id: svn://svn.transmissionbt.com/Transmission/trunk@13836 f4695dd4-2c0a-0410-b89c-da849a56a58e
(libT) #1220 'change file and folder names': handle .part file suffixs

git-svn-id: svn://svn.transmissionbt.com/Transmission/trunk@13837 f4695dd4-2c0a-0410-b89c-da849a56a58e