setslice of ``[0:0]`` correctly, which in particular could occur
when using ``insert(0, item)`` with the association proxy.  Due
to some quirk in Python collections, the issue was much more likely
with Python 3 rather than 2.  Also in 0.8.3, 0.7.11.
[ticket:2807]

- rework the event system so that event modules load after their
targets, dependencies are reversed
- create an improved strategy lookup system for the ORM
- rework the ORM to have very few import cycles
- move out "importlater" to just util.dependency
- other tricks to cross-populate modules in as clear a way as possible

proxies, they aren't overriding getattr() or setattr() at all.  so all the
hardcoded getattr()/setattr() is removed from collections.py.   Lots of these
getattr/setattr were against the attributeimpl and decorated functions
and don't seem like they'd ever be needed; for a user that needs special access
to a collection, we can evaulate that use case and add a single point of
"unwrapping", and probably add a hook for it via
InstrumentationManager so that the collection implementation isn't complicated
by it.

as possible

- went through examples/ and cleaned out excess list() calls

method, which fires off each time the collection is associated
or de-associated with a mapped object - the decorator
was not tested or functional.  The decorator method
is now named :meth:`.collection.linker` though the name "link"
remains for backwards compatibility.  Courtesy Luca Wehrstedt.
[ticket:2653]

collections, mainly that the usage of the @collection decorators
will now honor the __mro__ of the given class, applying the
logic of the sub-most classes' version of a particular collection
method.   Previously, it wasn't predictable when subclassing
an existing instrumented class such as :class:`.MappedCollection`
whether or not custom methods would resolve correctly.
[ticket:2654]

- The undocumented (and hopefully unused) system of producing
custom collections using an ``__instrumentation__`` datastructure
associated with the collection has been removed, as this was a complex
and untested feature which was also essentially redundant versus the
decorator approach.   Other internal simplifcations to the
orm.collections module have been made as well.