Log Message:
Update to 0.6.20.

New in 0.6.20; 2010-02-16; Andreas Jellinghaus
* Modify Rutoken S binary interfaces by Aktiv Co.
* Makefiles fixed in doc/ directory

New in 0.6.19; 2010-01-07; Andreas Jellinghaus
* update on udev rules. Please now use udev instead of hal,
  as distributions are deprecating hal in favor for udev.
* Thanks to Daniel Kahn Gillmor for testing on debian.