Date range fields should be visible.

The date range fields labeled "upper" and "lower" in the main form are presently invisible to humans. Initially this was done to keep the visual footprint of the search form as low as possible. Through using the tool however it has become apparent that these fields are in fact necessary and should be exposed.

1. Make the lower and upper fields visible on the form.
2. Implement the DatePicker javascript class as seen in Wombat (http://wiki.worldforge.org/wiki/Wombat, source for js is in the public directory within the git repository)
3. Ensure that A. Date fields specified manually are compatible with the current ajax submission process (submitAjaxSearchFormExtended() method); B. Date fields specified manually are compatible with the php search results method in Brutus and C. Date fields specified manually may still be altered correctly by the previous/next links in the table header of results.