Improved the way URLs are automatically detected in posts

It seems parentheses bring a lot of trouble to actually perform an appropriate parsing. In short, I'm now removing the last closing parentheses if it doesn't have matching parentheses in the URL. These are the URLs I used to test:

(http://www.blahblah.com)
[http://www.blahblah.com]
http://www.blahblah.com
http://www.blahblah.com/sldkfjs/sdf.html
http://www.blahblah.com/sldkfjs/s&sdf%29df.html
http://www.blahblah.com. => This fails in 1.6.3
http://www.blahblah.com/.
http://wikipedia.org/wiki/sdf_sdf_(asd_asd_) => This fails in 1.6.3
http://blahblah.com/aha/aa752574(VS.85).aspx => This fails in 1.6.3

Related Q2A post: http://www.question2answer.org/qa/29015