adding more user agents found frequently in logs

Adding user agents frequently found in our site logs not caught by browser gem:

```
netEstate NE Crawler (+http://www.website-datenbank.de/)
AddThis.com robot tech.support@clearspring.com
RelateIQ Crawler www.relateiq.com
````

Also found baidu spider:
````
Mozilla/5.0 (Linux;u;Android 2.3.7;zh-cn;) AppleWebKit/533.1 (KHTML,like Gecko) Version/4.0 Mobile Safari/533.1 (compatible; +http://www.baidu.com/search/spi_der.html
````

Since it was in the bots file twice with the same value, I changed one value to include just `baidu` instead of `Chinese search engine`.