WebSearch: improved search interface.

• Adds search box with autocompletion.

• Uses new search settings menu with extended bootstrap-select.js

• Improves and cleanes facet JS plugin. It warns when item already exists and allows only one (key, value) either in limit to or exclude filter.

• Supports search field autocompletion of authors (author:Elli).

• Uses facet menu affix bootstrap plugin to stay always visible.