Our array abstractions should be removed, and substituted with modern data
structures.
  
Templatized vectors are:
 - type safe
 - easier to read/maintain
 - faster

Also: remove some dead code.
The class Database_ids is unused, which means we can remove it,
and the base class Dynamic_ids.
The member function Server_ids::do_search_id is also unused,
and can be removed.

The macro sort_dynamic() is no longer in use, and can be removed.

There was a bug in change_receive_options():
If we are inserting multiple ids into mi->ignore_server_ids
then we need to re-sort before doing a binary_search.
The old code worked "by accident", bsearch() found an element,
even though the array was no longer sorted after an insert_dynamic()

The fix for the sort/bsearch() bug: implement insertion-sort in Prealloced_array,
and use insert_unique() to keep the array sorted at all times.
This is a short array of ints, with pre-allocation, so insert-sort should be fairly efficient.