This PR replaces the global strict exception mode with an option to
handle `Exception` per function while at the same time enabling strict
exception checking globally by default as has been planned for v4.
`handleException` mode raises `AsyncExceptionError` to distinguish it
from `ValueError` which may originate from user code.
* remove obsolete 1.2 config options
* Introduce chronos/internals, move some code
This PR breaks the include dependencies between `asyncfutures2` and
`asyncmacros2` by moving the dispatcher and some other code to a new
module.
This step makes it easier to implement `asyncraises` support for future
utilities like `allFutures` etc avoiding the need to play tricks with
include order etc.
Future PR:s may further articulate the difference between "internal"
stuff subject to API breakage and regular public API intended for end
users (rather than advanced integrators).
* names
* windows fix