Add a function "callbackToNode"

Doc and example in the code
Use of function sort instead of sorted
Merge branch 'f_misc1' into ours

* f_misc1:
  Patch for the constantLine function
  Error with different format of "from" and "until"
Merge branch 'f_callback' into ours

* f_callback:
  Use of function sort instead of sorted
  Add a function "callbackToNode"