Feature request: being able to collapse parts of the stack trace #94

It'd be great if it were possible to collapse some parts of the trace.

My use-case is that I use TraceGL with a Backbone app and I'd like to hide some repetitive parts when a UI is constructed. For example, when displaying a list of items, the same functions will be called for each one and it can get very long. I then lose track of the bigger picture.