Twitter hashtag and @ converter breaks text

After updating from Twitter version from 7.x-5.8+11-dev to 7.x-5.11/7.x-6.2/7.x-6.2-dev I started having issues with the module: 

I noticed that the input filter was converting HTML entities into Twitter hashtags (apostrophes are written as ') and converting urls with @'s to usernames in the body of the nodes. On my Text Filter configuration I have the "convert Twitter usernames" and "convert Twitter hashtags" checked.

When googleing for help, I found out my issue was related to others, such as missinterpreting of CSS style codes and @usernames between parentheses.

I realized the problem was the _twitter_filter_text() function, so I propose a patch (which is basically going back to the previous version of the function + some minor changes) and add a twitter_filter_text.test file for this special function testing each of these cases I explained above. I think it could be helpful in the future, to make sure that new changes don't mess up former functionalities.