Add `get_label_profiles()` method for LabelHandler

just to make sure same logic is used in tailbone and byjove/api

Massive overhaul of "generate project" feature

previous incarnation was woefully lacking. new feature is much more
extensible. still need to remove old POS integration specifics in
some places.

and a couple of unrelated things that snuck in..

- deprecate `rattail.util.OrderedDict`
- deprecate `rattail.util.import_module_path()`
- deprecate `rattail.util.import_reload()`

Do not cache label printer, formatter

the label handler may be long-lived and so must avoid cache to reflect
changes made in real-time

Deprecate the old `rattail.db.api.settings` module

technically this is still being used here and there in the wild, but
that really needs to stop so that we can guarantee validity of beaker
cache when that is being used

Let label batch provide product prices when executing

plus refactor label printer / formatter logic a bit

Switch license to GPL v3 (no longer Affero)

refs #2

General header / Unicode cleanup.

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

Improve Unicode handling within some label printing logic.

This probably isn't finished yet...

Refactored model imports, etc.

This is in preparation for using database models only from `rattail` (i.e. no
`edbob`). Mostly the model and enum imports were affected.

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.