If `LoopProc` fails, it should probably just throw an exception.

This silences several compiler warnings about `error` not being used.

Use `new` and `delete` instead of `AllocCom` (`FreeCom`) as allocators
from the dimension-dependent can no longer be used.

The counters might be used by the various initialization functions and
therefore have to be set to zero earlier.

This worked previously as variables with static storage duration are
zero-initialized and DDD left them at zero when exiting as well.
However the context object's member variable is not zero-initialized
so this broke with the change as at least `nCplItems` was used by
`ddd_IFInit`.

Also provide a compat version of `DDD_InfoProcList` that uses the
global DDDContext object.

This also eliminates the global variable `currentObjectMem`.

`LC_MSGTYPE` and `LC_MSGTYPE` are used in the global state of cons.cc.

Each `IF_PROC` object already has two buffers which calls memory
allocation functions, so one more allocation for the `IF_PROC` object
itself should be acceptable.

The number of different attributes should also be small, so allocating
`IF_ATTR` directly instead of using a free list should also be
okay (although there are `IF_ATTR` instances for each `IF_PROC`
object).

Also use constructors which initialize most members to make the code a
bit more readable.