Handle symlinks and character devices

[polar9000]

I was testing pyaff4 with an M1 Mac attached to another Mac using Mac Sharing mode, but it stalled after a short while. The last few lines of console output are:

	Adding: /Volumes/Untitled/Volumes/Untitled/Applications/iTerm.app
	Adding: /Volumes/Untitled/Volumes/Untitled/Applications/Developer.app
	Adding: /Volumes/Untitled/Volumes/Untitled/Applications/Firefox.app
	Adding: /Volumes/Untitled/Volumes/Untitled/dev/console

• /Volumes/Untitled is where the M1 Mac is mounted (using sharing mode) on the second Mac.
• /Volumes/Untitled/Volumes/Untitled is a symlink to /.
• /Volumes/Untitled/Volumes/Untitled/dev/console is therefore /dev/console on the second Mac.

pyaff4 should not follow symlinks and it should not try to read /dev/console.