SL Backcompat Plan:

*** dynamic schemas

* should default to 0.04006 mode
* __PACKAGE__->naming('current') will turn on current mode

*** 0.04006 mode

* use the detector and compat relbuilder ilmari already wrote for static schemas
* add a loud warning that says that we're running in backcompat mode, and refers
  to the ::Manual::UpgradingFrom4006 POD.

*** 0.04006 tests

* are in t/backcompat/0.04006
* have their own lib/
* should only run with the SCHEMA_LOADER_TESTS_BACKCOMPAT=1 env var
* need tests_recursive (or whatever) in Makefile.PL
* need to run in 0.04006 mode (by seeding with a Schema.pm generated by
  0.04006, activation of backcompat mode should be minimally invasive.)

*** Schema::Loader::Base

* 'naming' accessor should be a Class::Accessor::Grouped 'inherited' type
  accessor, doc is written

*** Write ::Manual::UpgradingFrom4006 POD

*** Catalyst Helper

* Add 'upgrade=1' option that upgrades from both old S::L and old helper,
  whichever or both.
* Warn when old helper output or 0.04000 S::L output is detected, that refers to
  the upgrade option.

Release dev S::L, announce to catalyst, dbic lists and #catalyst that testing of
backcompat mode is needed, wait 2-3 weeks, then release 0.05000.