Add alternative time smoother implementation
This patch set adds a new time smoother to PA, which delivers higher precision than the current version. More details in the commit message of the first patch.
The first patch adds the functionality, the other patches are a straight forward addition of the new smoother functions to all callers of the time smoother. A configure option is used to switch between the two smoother implementations. It is currently disabled by default but should be enabled once some broader testing was done.
The last three patches could not be tested, so any tests would be appreciated.