[Cs3] iterator invalidation rules

[Mikhail Nesterenko]

CS3 students,

Iterator invalidation rules are rather extensive. Here is the complete
list:

  http://kera.name/articles/2011/06/iterator-invalidation-rules/

For splice, according to this, no iterators are affected, the spliced
in list iterators now iterate over the "outer" list.

 http://www.cplusplus.com/reference/list/list/splice/

Thanks,
-- 
Mikhail