(trunk, libT) #4160 'foreign character support' -- merge mike.dld's 4160-02b-path.patch, which updates the codebase to use the new tr_sys_path_*() portability wrappers introduced in 4160-02a

git-svn-id: file:///data/workdir/Transmission-svn//trunk@14320 1bcf1a7e-6170-4b50-b784-84ec52b2dec6
(trunk, libT) #4160 'foreign character support' -- merge mike.dld's 4160-03a-file.platch, which introduces tr_sys_file_*() portability wrappers

git-svn-id: file:///data/workdir/Transmission-svn//trunk@14321 1bcf1a7e-6170-4b50-b784-84ec52b2dec6