Filters and Highlights

I've pushed a few extra things I've added whilst using sleepy to track down performance bottlenecks

This adds:

* A filters pane - lets you quickly filter the displayed trace entries to a particular function name, module or sourcefile (including substrings, so you can, for example just show MyClass:: or code in C:\mycode\myapp\) - right click entries to quickly set filters, or enter them manually in the Filters tab

* Right click an entry to highlight it - makes it much easier to find the function you're looking at when changing filtering / sorting / etc

* Displays the filename of the dump in the titlebar, so if you're comparing multiple dumps, you can easily see which is which