Time lines

The following routines are available for creating and changing time lines. Don't change time lines that are in use!

timeline_add() Adds a new time line. It returns the index of the time line.
timeline_delete(ind) Deletes the time line with the given index. Make sure no instances uses the time line in any room.
timeline_clear(ind) Clears the time line with the given index removing all its moments. Make sure no instances uses the time line at the moment.
timeline_moment_add(ind,step,codestr) Adds a code action to the time line at moment step. codestr contains the code for the actions. If the step does not exist it is created. So you can add multiple code actions for the same moment.
timeline_moment_clear(ind,step) You can use this function to clear all the actions for a particular moment.