Look in user's home directory for .faketorio file

[danielbrauer]

Uses the HOME environment variable on Unix, and USERPROFILE on Windows. I've tested the former and it works great. Not sure about the latter.

I didn't add an automated test for the normal case because it would really just be re-implementing the behaviour to get a string to compare against. I did test for the case where we don't find the environment variable, though.