Add --copy-links, use stat instead of lstat
Add --copy-links, use stat instead of lstat

To properly sync symlinks, use stat instead of lstat, otherwise we get the size
of the link (instead of the file) and we end up constantly re-pushing
everything. Also add a --copy-links/-L option that enables syncing of symlinks,
similarly to rsync.

google/adb-sync,google/adb-sync