Remove alembic import from `db.util` module

Also bump the alembic version requirement, to ensure support for
multiple migration bases.

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

Trying to make more of an effort here...

Add bulk Rattail importer, plus various tweaks

Tweaks are mostly for the sake of a `host_session`, if one is involved.

Make 'commands' subpackage, add 'rattail-dev' command.

And add subcommand for 'rattail-dev new-batch'. Hopefully this is all a
good idea, pretty rough draft at this point.

Add initial `clonedb` command.

Needing a way to fire up some mock databases with Postgres...

Revert "Add version restriction for SQLAlchemy-Utils."

This reverts commit 22a713b40f02e748f81db0704bf2113ab5cd3414.

I think this is no longer an issue?

Add 'datasync' daemon.

First attempt, but already seems to work as good or better than 'dbsync'.

Remove `make-config` command, and edbob dependency!

The `make-config` command still seems like a good idea, but hadn't been
implemented properly, and was just an eyesore at this point...

Overhaul config system, finally replacing edbob (yay!).

* No more `edbob.init()`, now we use `rattail.config.make_config()` instead.
* Adds new `ConfigExtension` mechanism to replace old 'init' config magic.
* Adds config extension for `rattail.db`, to load all Rattail db engines.
* All application entry points have been updated to use `make_config()`.

This also refactors `rattail.db` somewhat in general, to allow for safely
importing it without getting SA-related import errors.

Add 2nd version of UNFI catalog parser.

Apparently they've changed their format. Hopefully this versioning idea is
a good one...

Add version restriction for SQLAlchemy-Utils.

Hopefully that can be removed soon...

Add vendor invoice parser for Albert's Organics.

Also tweak parsers for KeHE and UNFI, for consistency.

Wrap up initial vendor catalog batch support.

This adds some more contrib catalog parsers, and (hopefully) improves some
of the core cognizing logic. Also refactored some progress factory args.

Try again to make database stuff an optional dependency...

This really does need to happen, hopefully we can get it right soon.

Add `import-csv` command, and `db.importing.providers.csv` module.

Refactored `db.importing.providers` slightly to make this possible.

Initial commit of new batch mixin system...

Attempt number 5,176 at finding a good way to make flexible batches.

Move bcrypt requirement into 'auth' extra feature.

For the love of God can we please not require this on Windows...unless we
truly need it.

General header / Unicode cleanup.

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

Add Mako dependency...at least for now.

Would perhaps be better to make this optional or some other clever thing.

Revert "Stop using `find_packages()`; it was including tests."

This reverts commit 7b76df43668e764ce1d1630a0dba462193935a77.

Added `--do-not-daemonize` arg to `filemon` command on Linux.

Also removed some of the dependence on `edbob`.

Prepare for tests.

This doesn't add any actual tests but it should pave the way for that. Tests
may be run like so:

{{{
python setup.py nosetests --with-coverage
}}}

Added `make-config` command.

This may need some work yet, to better handle the namespace package situation.

Renamed CHANGES file.

Added ``.rst`` extension for a better editor experience.

Added `purge-batches` command.

This command will delete forever all batches whose purge date has
passed. It is meant to be run on a scheduled basis, e.g. nightly.

Added Palm OS app interface.

This commit adds the Palm HotSync conduit, which is used to create CSV
files when a handheld running the Rattail app is synced with its
desktop PC.

extended commit (see note)

- Added ``Store`` and related models.

- Added ``Customer.email_preference`` field.

- Added ``load-host-data`` command.

- Added ``Change`` model.

- Added ``rattail.db.record_changes()`` function.

- Added database synchronization service (Windows only).

extensive commit (see note)

The following changes are included:

- Initial batch support added (with ``PrintLabels`` provider).

- GPC data type added.

- Changed internal name of file monitor.

- Added progress support for label printing.

- Label profiles moved from config to database model.

- Removed ``rattail.db.init_database()`` function.

- Moved some enum values from db extension to core (``rattail.enum`` module).

- Improved SIL support: moved ``rattail.sil`` to subpackage, added ``Writer
class etc.