Change the main() method signature to include CLI arguments.

Eases debugging, might prove useful for something else eventually.
Comment cosmetics.
Initialize syslog logging at the beginning of the file.
Whitespace cosmetics.
Whitespace cosmetics: break lines.
Remove a FIXME, add a comment.
Debug log the CLI arguments we received.
Iterate FUSE's dict options and search for our custom option pyroot.

It tells us the root to use.
This is useful when trying to mount pyarrfs via /etc/fstab.
Debug log the root and mountpoint before actually mounting.