Modified ordered view frame to use cache.
faster check for grouping
modified nonnumericProcessLevel to look up items only if they get printed
proper handling of missing items
Replicated new ordered view frame design from text to numeric value types
Add "top-k" sorter to speed presenting short prefixes of all items.
Instead of sorting whole list to select top, extract top and then sort.
Exploited some more caching opportunities in order view frame.
factored duplicate code for order/possible order configuration
bugfix
Allow extensions to load using standard script tags.
Several people have run into trouble switching to exhibit 3 because of
the change to using link tags to load extensions.  So, I've modified
exhibit (and the two main extensions, map and timeline) to work if
they are included as scripts instead of links.  This involved a little
bit of messy code on exhibit-api.js and exhibit.js , but I think it's
worth it to permit easier transition to E3.
Merge pull request #61 from karger/2013-10-30_orderedViewFrame_cache

2013 10 30 ordered view frame cache
Merge pull request #63 from karger/2013-11-01_extension_loading

Allow extensions to load using standard script tags.