Character Limit does not accurately match URL t.co wrapper

[GoogleCodeExporter]

What steps will reproduce the problem?
1. PostUpdate via the API with a tweet that is > 140 characters with original 
URL, but < 140 characters after automatic URL t.co shortening

What is the expected output? What do you see instead?
The tweet should be successful, but we receive an error message that the tweet 
is > 140 characters.

What version of the product are you using? On what operating system?
0.8.2, Gentoo Linux

Please provide any additional information below.
The API will notice that the tweet is > 140 characters and stop you, but if you 
entered the same tweet into the twitter browser box, it would become valid due 
to the automatic t.co URL shortener. I believe all URL's > 19 characters will 
be shortened to 20 characters. I increased my character limit in twitter.py to 
bypass the check and my tweets are now working fine... you possibly need to do 
a check if a URL exists in the message, and if so assume it's 20 characters and 
make sure message is <=120 characters... As far as I know

Original issue reported on code.google.com by [email protected] on 11 Nov 2012 at 12:08