Merge remote-tracking branch 'refs/remotes/tachycline/master' into Problem-1.9

[tkorda]

I had trouble in the begining when normalizing Psi. As a result all my output is bizzare but I could not find discrepancies in the code you used from my own. Also when finding the expectation values, I was unable to find P^2. An error message that I could not understand would appear. I also compared this code and coulkd not find a difference between it and the reference.

[tachycline]

I'm not exactly sure what you've done, so I can't comment on what might have gone wrong. If you work on each problem in its own branch (use the 'create branch' button), it's a little easier to keep track of what you're doing.