109.39.00

- Added support for additional predictors like minor/major GCs and
  compactions, using multi-variable linear regression.

  Replaced linear regression with multi-variable linear regression.
  The original algorithm estimated the cost of a function `f` by using
  a linear regression of the time taken to run `f` vs the number of
  runs.  The new version adds the ability to include additional
  predictors such as minor GCs, compactions etc.

  This allows a more fine-grained split-up of the running costs of a
  function, distinguishing between the time spent actually running `f`
  and the time spent doing minor GCs, major GCs or compactions.
- Added a forking option that allows benchmarks to be run in separate
  processes.

  This avoids any influence (e.g. polluting the cache, size of live
  heap words) they might otherwise have on each other.
109.40.00