fix: move "record changes" global hook to startup()

this silly thing shouldn't even exist but can't remove until i'm
certain it's not in use in the wild.

but at least, it shouldn't be triggered when a config object is
instantiated, it needs to be deferred a little. should not affect app
runtime per se but more helpful for tests.

feat: refactor config/extension, session logic per wuttjamaican

this leverages wuttjamaican for a few more things perhaps, but mostly
this is to organize the code in a more logical way based on
conventions used in wuttjamaican.

fix: remove duplicate method for `RattailConfig.production()`

since it now is defined in `WuttaConfig`

feat: move some app model logic to wuttjamaican

previously the "canonical" way to get the model was via
config.get_model() - but now the canonical way is simply app.model

note that for now, even though wuttjamaican provides a default model,
the rattail model does not (yet?) inherit from it. also since
wuttjamaican does not yet support versioning, that feature remains in
rattail only for now.

various legacy things have been deprecated and will warn if used by
other apps.

fix: refactor code so most things work without sqlalchemy

also refactor tests to help ensure that remains true

fix: change how we override default app handler, engine maker

per upstream changes. this ensures we avoid the app handler when first
creating the engines, so that config extensions may override the
default app handler without being ignored.

test: improve some tests, docs for `rattail.config` module

still some left to do, just a stopping point

fix: deprecate `parse_bool()` and `parse_list()` in `rattail.config`

those are provided by `wuttjamaican.util` now instead, but also the
`RattailConfig` methods

Remove the `RattailConfigWrapper` class

just using `RattailConfig` directly now

Add wutta wrapper for `make_config()`

this needs more work, it's not a true wrapper yet. but it's a
conceptual wrapper at least and uses upstream `get_config_paths()` now

Add wutta wrapper for `short_session()`

and several related tweaks for tests, docs

Add `RattailWuttaConfig.getdate()` compatibility method

and improve related logic, tests, docs

Incorporate the WuttJamaican package

- our AppHandler is now based on that one
- our Config *may* be based on it, if so configured

at some point our Config will "always" be based on WuttaConfig but we
need to test a bit more first

Move tests out of the installed package set

this seems to be better practice. from what i can tell this is a
clean move with no breakage.. and built package files no longer seem
to include test modules

Make 'tests' a proper subpackage again; add some tests

Trying to make more of an effort here...

General header / Unicode cleanup.

This hopefully updates all module headers such that the file encoding is
utf-8, and uses Unicode literals, etc.

Add `rattail.config` module, move `parse_list` function there.

This function is already proving useful in other contexts besides just the
file monitor.