Computing sizes in library

[bsherin]

• [x] Computing collection sizes works
• [x] Computing project sizes works
• [ ] Computing can take a while the first time in collections. Display a message?
• [x] If a collection was saved before gridfs, then it will get a size of zero. When the collection is copied, this size of zero is copied over, so it doesn't get fixed.
• [x] In places where a single new row is added in the library (such as on duplication) then I don't get the size information
  • I've tried to handle a bunch of these but haven't test them. Also, in the process I changed how all of this machinery works.

[bsherin]

I think this is good enough