"Matrix" URIs used by schema_filter view are problematic

[slinkp]

Eg. /restaurants/filter/by-date:2006-01-01,2006-01-02;locations=zipcodes,12345/

This is problematic for several reasons:

• there's no real benefit vs. using query strings (except a theoretical benefit that some caching proxies don't like to cache URLs that have query strings)
• supporting it requires a bit of custom parsing code
• yet another thing for developers to need to learn
• users don't understand if/how they can modify the URI
• adds a hoop to jump through before richmaps and REST API code can leverage the same db.schemafilters code that db.views uses

By contrast, everybody understands query strings and they require less code to implement.

We should also move away from packing several pieces of data into one comma-separated value, for the same reasons, but that can be tackled later.

So the example URI would be something like:
/restaurants/filter/?start_date=2006-01-01&end_date=2006-01-02&locations=zipcodes,12345

[slinkp]

Fixed in f9de3a071de31c2330c09829345ebe75ff4453e1