Add:
    static/js/index.advanced-search-form.js, static/sass/index.sass,
    static/css/lib/jqueryui.custom.min.css
        -Add `jQuery UI` autocompletion menu to the advanced-search form's
        language input field, to replace `twitter typeahead` (which was
        incompatible with the new form's style rules).

    static/js/index.advanced-search-form.js
        -Add regex field specifier to query string.

Add:
    static/js/index.advanced-search-form.js
        -Add `assembleQuery()`, which constructs a query string from the
        contents of the fields of the advanced search form's search groups.

Add:
    static/js/(index > index.advanced-search-form).js
        -Migrate code relevant to the advanced search form to its own file.
        -Group global-scope function calls into wrapper functions executed on
        definition.
        -Add datepicker to new form's input fields.