Update coro() method to return create and wrap values.

[johnd0e]

This is commit from far-support branch: 0801f18

Discussed here: http://forum.farmanager.com/viewtopic.php?p=116873#p116873

Edit
The idea behind current coro is great: to hide all tricky doings into 1 high level function.
Unfortunately, it's not bullet proof enough, and to handle possible issues one must clearly understand what exactly is happening inside (and due to lack of documentation it's necessary to inspect mobdebug source code).

Thus the idea of 'highlevelness' of this function gets completely destroyed.
So I propose to make things a level lower, but a lot clearer way.