Minor string tweaks
handlerToWidget considered harmful. Fixes #3

This should fix all of the n+1s except those in the admin area. Those
are alright for now, as it'll mostly just be me using them on my local
machine.
Clean up a few TODOs
Attempt to log current path on error
Extract non-search related Handlers from the Handler.Search
Simplify pluralization helper

I'll add a pluralize' if anything is ever more complicated
Add 404, 500 pages
Include property results in text search. Fixes #6
Remove unused proof#theorem_index column
Improve deduced trait display #19

This gets the HTML side to where it should be and starts implementing a
JSON endpoint that will eventually be used for a more interactive
display.
Fix trait and theorem titles