Contribution from Steffen Dalgard

The program reuses timer, extends customprinter and add three new process types sender, printIncrementForward and ender

The sender process sends a token each time timer expires
The token is an integer number that is sendt through a chain of 6 printIncrementForward processes
   The process prints the number, increments it and forward it to the next
The ender loops back the token through the same chain.
  This time the number is decremented

Expected output for each time the timer expires is:
Sender sends token ...  1  2  3  4  5  6  ... Ender returns token ...  6  5  4  3  2  1  Sender got token back