some tracing notes

[Ryan Hileman]

1. in imgtrace, color or brighten the memory based on the instruction pointer when it was accessed, which allows to see when in the runtime of a program the memory was accessed
2. grouping the side effects by function calls (which is tiered/nested), and allowing transformations at that level, like "this loop does these calls and has these side effects")
3. adding global filters (like "don't step into this function", or "don't show side effects from this function") that work over time! so you can set a filter as you're going, then rewind and it's still applied