Fix class search issues

[maximz]

• “Affordable care ac” works but “affordable care act” doesn’t, because 3-letter words are treated as department names. (Reproduced 9/18/16 for Spring 2015-16.)
• Problem with "and": "Modern genetics an" works, "Modern genetics and" fails. (Reproduced 9/18/16 for Fall 2016-17).

Perhaps refactor search to work faster, per @bnprks's suggestion: compile one string for each class and just search through this one list of strings, not all object properties. That’s why search is so fast on http://bparks.mycpanel.princeton.edu/search/

@bnprks, want to take this on?