UI improvements

Collapse the activity contexts by default and show a summary of the logs.
![elmlogger7](https://cloud.githubusercontent.com/assets/2818455/5291098/1974b9ae-7b03-11e4-8688-8718e723fed4.png)

The server has the information but the view is actually where the tree is expanded out. I think I can keep track of the count there and toggle between the collapsed/expanded views.