fix a localized date string issue and add new config options to use user defined ticket status

This pull request resolve 2 problems. Could you review it?

## fix to decode the date string from solr

The datetime.strftime() might return encoded date string depending on locale. And Genshi expects the unicode string.

```python
>>> import locale
>>> import datetime
>>> locale.getlocale()
(None, None)
>>> print datetime.datetime.now().strftime("%a %b %d %Y")
Thu Nov 21 2013
>>> locale.setlocale(locale.LC_ALL, 'ja_JP.UTF-8')
'ja_JP.UTF-8'
>>> locale.getlocale()
('ja_JP', 'UTF-8')
>>> print datetime.datetime.now().strftime("%a %b %d %Y")
木 11月 21 2013
```

## add 'ticket_status' and 'ticket_status_enable' config options

We use the custom ticket status for our purpose. The plugin handles only default ticket values. So, it doesn't show search result if the ticket status is not default.
```python
('new', 'assigned', 'reopened', 'closed')
```