Display function percentage of total in symbol view

I've added % of total request to the inclusive metrics for the current and parent functions in a symbol view. I found this helpful when looking at expensive functions as knowing how expensive relative to the request they are helps focus effort on methods with larger impact.  The new view looks like:

![screen shot 2014-05-11 at 9 43 33 pm](https://cloud.githubusercontent.com/assets/24086/2940222/2ddc8b66-d977-11e3-85b0-3fd39bd0e491.png)