stop bothering to log presenter connections in activity

They can't be cleaned up when the presenter disconnects, so let's just not log them as activity.
Fix how virtual attributes are accessed

This is deprecated in Rails 3.2 and throwing deprecation warnings in the console.  Going to break in Rails 4. (I imagine our hacked PaperTrail will break in Rails 4 as well).
Merge pull request #227 from extension/clean_up_pc

Fix issues with Presenter Connections