* FIX: 'false' value was treated as a truthy value
For example, latest.json?no_subcategories=false used to have set
no_subcategories to the string value of 'false', which is not false.
* DEV: Remove dead code
* FIX: Redirect to /none under the right conditions
These conditions are:
- neither /all or /none present
- only for default filter
* FIX: Build correct topic list filter
/none was never added to the topic list filter
* FIX: Do not show count for subcategories if 'none' category
* FIX: preload_key must contain /none if no_subcategories
df26d2e72a