Massive refactor:

* Symbolized everything. All filter names, column names, group_by attribute - everything's a symbol.
* Accidentally left out all the sort criteria stuff.
* Changed column_names field to columns.
* Broke out QueryableQuery into modules.
* Changed acts_as_queryable syntax to be more consistent.
* Moved basically all non-structural view output into helpers for customization.
Remove console.log and Engines reference.