per-core/NUMA CPU and disk utilization plain-text grapher

 This is a top-of-the-line logger of CPU usage patterns, designed for
 machines with ca. 50-300 total hardware threads (fewer works but results
 in a narrow graph, more requires a very wide terminal). Every per-tick
 sample is shown abusing Unicode characters to fit within a single line.
 .
 Disk usage is also shown in a similarly terse per-device way, as %
 utilization for reads and writes.