revisit orderinglist for 0.4

[jek]

The _raw_append can probably be the @appender now that that's possible, and reorder_on_append can be deprecated.

[jek]

Nope, not so much. The old way is still desirable due to the mechanics of collection bulk-assignment. E.g. such that

entity.children = [Child(), Child()](Child(),)

will continue to number children as they append to the collection. (These each get run through the @appender)

[Mike Bayer]

Removing milestone: 0.4.0 (automated comment)