Add an (scrap or map) element reference to this map.
When adding a File_Therion_Scrap object, the scraps -id option will be used as reference. The same is true for File_Therion_Map. To resolve the line objects using a given scrap object, use dereferenceElements().
Note that Maps may contain scrap references of map references, but not both! Therion will complain.
The special "break" string may be used to adjust level rendering in the map output.
The optional index parameter allows to adjust the insertion point; the line will be inserted at the index, pushing already present content one line down (-1=end, 0=start, ...). When replacing, the selected index will be replaced.
Instead of $index 0 and -1 you can use the strings 'start'/'end', this will make your code more readable. Using addLine(..., $lln - 1)
will use logical line number instead of the index (logical = index+1).
Note that for therion the ordering matters. See the therion documentation for more details.
Parameters: