patch applied (packages/time): Add secondsToDiffTime and picosecondsToDiffTime.

[bjorn at bringert.net]

Wed Nov 15 14:21:45 PST 2006  bjorn at bringert.net
  * Add secondsToDiffTime and picosecondsToDiffTime.
  Rationale: 
  As has come up on haskell-cafe
  (http://comments.gmane.org/gmane.comp.lang.haskell.cafe/15653), it
  takes a while to figure out how to make DiffTime values.
  
  secondsToDiffTime is not that important since it is just another name
  for fromInteger, but I suspect that it would be used a lot.  Using
  fromRational to create a DiffTime from a number of picoseconds is a
  bit of a hassle, so having a picosecondsToDiffTime would be useful.

    M ./Data/Time/Clock/Scale.hs -1 +11