"Create a new score set" experiment dropdown

[afrubin]

The dropdown for selecting an experiment on the new score set creation page should include the experiment URN somewhere, maybe in parentheses or brackets after the experiment name.

The dropdown should also exclude experiments that were created to hold meta-analysis score sets, since it shouldn't be possible to add score sets to these directly.

I'm not sure how the list of experiments is sorted, but it would be useful to sort it such that any unpublished (tmp) experiments appear at the top of the list.

[bencap]

Closing in favor of #294, #295, and #296.