Log Message:
Update to 1.4.22:

1.4.22
==================================================

- refactor class-level registry on ForkedFunc child start/finish
  event to become instance based (i.e. passed into the constructor)

1.4.21
==================================================

- ForkedFunc now has class-level register_on_start/on_exit()
  methods to allow adding information in the boxed process.
  Thanks Marc Schlaich.

- ForkedFunc in the child opens in "auto-flush" mode for
  stdout/stderr so that when a subprocess dies you can see
  its output even if it didn't flush itself.

- refactor traceback generation in light of pytest issue 364
  (shortening tracebacks).   you can now set a new traceback style
  on a per-entry basis such that a caller can force entries to be
  isplayed as short or long entries.

- win32: py.path.local.sysfind(name) will preferrably return files with
  extensions so that if "X" and "X.bat" or "X.exe" \ 
is on the PATH,
  one of the latter two will be returned.