pll v0.3.2

Documentation only. The README now says that Span.Time reports a slot's scheduled time rounded down to whole nanoseconds, as its reference section always did. v0.3.1 was tagged on the v0.3.0 commit by mistake, so it is identical to v0.3.0 and is retracted.

pll v0.3.0

The first release under github.com/version2beta/pll. Version numbers below v0.3.0 belong to an earlier, withdrawn API and do not build under this module path.

• Rate: an exact number of units per second, from UnitsPerSecond or BitsPerSecond.
• Pacer: evenly spaced, numbered slots at an exact rate, with Due, Claim, Skip, NextDue and a trim in parts per trillion. Times never drift and the hot paths do not allocate.
• Span: a run of handed-out slots with their exact times, and an iterator over them.
• Follower: a type-II phase-locked loop configured by bandwidth and damping, with a lower-envelope window for jittery delivery, outlier rejection, steps when the other clock jumps, lock and holdover states, and a running jitter estimate. Its Trim drives a Pacer.
• cmd/pllsim: a deterministic simulator that runs the follower against realistic clocks and prints what it measured.