Add:
    static/js/index.advanced-search-form.js
        -Prevent the user from removing the last input field in an
        advanced-search group.

Rem:
    templates/index.html
        -Remove vestige code accidentally preserved during the c6e5b4f merge.

Add:
    templates/index.html, static/js/index.advanced-search-form.js
        -Remove commented-out code, `testQueryStringGeneration()`, etc.; prepare
        for merging into `develop`.

    static/js/advanced-search-form.js
        -Perform a live update of the main query bar with a user's inputs in the
        advanced search form.

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.