roverlay/strutil.py, unquote(): fix keep_going

unquote() needs to call itself with keep_going=True when operating recursively.
roverlay/fsutil.py, get_fs_dict(): fix

os.walk() should be called with my_root as dir, not initial_root (which is an
issue when initial_root is not an absolute path).
Not an issue for roverlay so far as get_fs_dict() gets called with abspaths
only.
roverlay/remote/rsync: remote redundant _set_status

RsyncRepo->_dosync(): don't call _set_ready()/_set_fail()

This is done by BasicRepo->sync() anyway.
roverlay/remote/websync: catch exceptions

Catch "unknown"/unhandled exceptions from urllib et al and set the repo's status
accordingly (similar to RsyncRepo).

Additionally, be a bit more specific about sync errors.
roverlay/remote/websync: handle connection timeouts

Wait up to URLOPEN_TIMEOUT(=10) seconds before giving up (and setting
want_retry). The timeout value cannot be changed in the config file.
config/repo.list, rstan: fix src_uri

This repo has been moved.