Generates a column sort link for a given attribute of a MetaSearch::Builder object. The link maintains existing options for the sort as parameters in the URL, and sets a meta_sort parameter as well. If the first parameter after the attribute name is not a hash, it will be used as a string for alternate link text. If a hash is supplied, it will be passed to link_to as an html_options hash. The link will be assigned two css classes: sort_link and one of "asc" or "desc", depending on the current sort order. Any class supplied in the options hash will be appended.

Sample usage:

  <%= sort_link @search, :name %>
  <%= sort_link @search, :name, 'Company Name' %>
  <%= sort_link @search, :name, :class => 'name_sort' %>
  <%= sort_link @search, :name, 'Company Name', :class => 'company_name_sort' %>
  <%= sort_link @search, :name, :default_order => :desc %>
  <%= sort_link @search, :name, 'Company Name', :default_order => :desc %>
  <%= sort_link @search, :name, :class => 'name_sort', :default_order => :desc %>
  <%= sort_link @search, :name, 'Company Name', :class => 'company_name_sort', :default_order => :desc %>