Unicode searches

[grapesmoker]

This PR wraps the search term in Django's smart_text Unicode converter so that you can do searches using Unicode characters in the search bar.

[grapesmoker]

Some background on what this PR does: the problem with the search turned out to be mostly about the Elasticsearch backend. In order to get Elastic to do things like turn Unicode characters (e.g. é) into their nearest ASCII equivalent, you need to enable an analyzer filter called asciifolding. Since the Elastic config is handled via haystack, the way to fix this is to add a settings dict that will be passed to Elastic when the index is built. This PR therefore has been updated to contain just such a dict; the settings also change the default tokenizer from standard to whitespace. The reasoning here is to allow users to search for things like "$500" (note the dollar sign); otherwise, many of those special characters are dropped during indexing.

This PR also adds a SuggestedSearchResult model which returns what we think are the most relevant results for a few specific search terms (e.g. "401k").

[Scotchester]

I'm not sure why Travis's tests are failing. They run fine for me locally, except for one Mystery Meet test (which fails because the fixtures were overridden by my loaded DB dump). That Mystery Meet test does not seem to be failing on Travis, though.

[Scotchester]

Per discussion in chat, we're going to go ahead with merging this and deploying it to our test server to see if there are any failures there.