position. iter will be changed to point to this new
row. If position is larger than the number of rows on the list, then the
new row will be appended to the list. The row will be empty after this
function is called. To fill in values, you need to call
gtkListStoreSet or gtkListStoreSetValue.gtkListStoreInsert(object, position)objectpositioniterGtkTreeIter to set to the new row