import now allows editing, moving people around

I also renamed some methods to make it more clear as to what it does and fixed the course enrollments per some hipchat (pending final confirmation of correctness though)
On Tue, Oct 21, 2014 at 07:31:58AM -0700, Brian Sadler wrote:
> Methods like this really get me nervous about the fact that we're still not doing unit tests.

Now that the LMS class is separate, we can write a mock object for that.

Though what I was more focused on testing was other details on canvas - like would existing assignments get changed? That's why it checks for the existing enrollment instead of just deleting them all, I wanted it to make as few changes as possible to do the update.