intel gpu meter - DO NOT MERGE

[tursulin]

This is just a quick&dirty sketch - DO NOT MERGE IT please.

My C++ is rusty, error handling is missing, graph drawing is poor, and most importantly question is whether xosview as a project wants something like this when it is specific to Intel GPUs in the first place. It's a sketch only. Feel free to peek inside, try it out and let me know your thoughts.

[needs CAP_PERFMON or relaxation of /proc/sys/kernel/perf_event_paranoid]

todo:

• error handling (logging?)
• fix line drawing

Signed-off-by: Tvrtko Ursulin [email protected]