Issue #371 - Remove dead code related to pagination.
Issue #371 - Consolidate paramKey and paramValue into a single string.

This way we can account for multiple params for a single dropdown
option. We handle the splitting of values in updateModelParams.
Issue #371 - Enable issues "sort" dropdown
Merge pull request #466 from webcompat/issues/371/1

Fixes #371 - Enable issues "sort" dropdown