Wagtailmenus

-----------------

* Changed the signature of ``Menu.render_from_tag()`` to better indicate common expected/supported arguments for menus.
* Added a custom ``render_from_tag()`` method for each individual menu class, with a signature that highlights all relevant options, including those specific to that menu type.
* Renamed ``Menu.get_contextual_vals_from_context()`` to ``Menu._create_contextualvals_obj_from_context()`` to give a better
indication of what the method does.
* Renamed ``Menu.get_option_vals_from_options`` to ``Menu._create_optionvals_obj_from_values()`` to give a better indication of what the method does.
* Added the ``Menu.get_from_collected_values()`` method, which replaces ``Menu.get_instance_for_rendering()`` for menu classes that also inherit from ``django.db.models.Model``.
* Added the ``Menu.create_from_collected_values()`` method, which replaces ``Menu.get_instance_for_rendering()`` for menu classes that **do not** inherit from ``django.db.models.Model``.
* Added the ``add_sub_menu_items_inline`` option to all template tags. When ``True``, ``SubMenu`` objects are automatically created and set as an attribute for each menu item (where appropriate), allowing developers to render multi-level menus without having to use the ``{% sub_menu %}`` tag.
* Added the ``WAGTAILMENUS_DEFAULT_ADD_SUB_MENUS_INLINE`` setting to allow developers to change the default ``add_sub_menu_items_inline`` option value for all template tags.
* Fixed a bug in ``Menu.get_common_hook_kwargs()`` where the value of ``self.max_levels`` was being used as the value for ``use_specific`` (instead of ``self.use_specific``).
* Changed the "Rendering setings" (typo) heading in ``panels.menu_settings_panels`` to "Render settings".
* Removed support for the deprecated ``WAGTAILMENUS_CHILDREN_MENU_CLASS_PATH`` setting.
* Removed support for the deprecated ``WAGTAILMENUS_SECTION_MENU_CLASS_PATH`` setting.
* Removed the deprecated ``wagtailmenus.constants`` module.

-------------------

* Fixed an issue with the section menu in the release notes section of the docs.
* Updated tox config to test against Python 3.7 and Wagtail 2.2.
* Updated Travis CI config to deploy to PyPi automatically when commits are tagged appropriately.
* Pinned django-cogwheels dependency to version 0.2 to reduce potential for backwards-incompatibility issues.

-------------------

* Added support for Wagtail version 2.1.
* Dropped support for Wagtail versions 1.10 to 1.13.
* Dropped support for Django versions 1.8 to 1.10.
* Updated trove classifiers in `setup.py` to reflect Django and Wagtail version support.
* Updated `runtests.py` to pass on any unparsed option arguments to Django's test method.
* Updated `runtests.py` to filter out deprecation warnings originating from other apps by default.
* Updated `MenuItem.relative_url()` to accept a `request` parameter (for parity with `wagtail.core.models.Page.relative_url()`), so that it can pass it on to the page method.
* Updated `Menu.prime_menu_items()` to send the current `HttpRequest` to that `MenuItem.relative_url()` and `Page.relative_url()`.
* Updated admin views to utilise `wagtail.admin.messages.validation_error()` for reporting field-specific and non-field errors.
* Removed redundant `install_requires` line from `setup.py`. Compatibility is made clear in other places - there's no need to force a minimum installed Wagtail version here.
* Moved custom `wagtail.contrib.modeladmin` classes out of `wagtailmenus.wagtail_hooks` and into a new `wagtailmenus.modeladmin` module.
* Added the `WAGTAILMENUS_FLAT_MENUS_MODELADMIN_CLASS` setting to allow the default `ModelAdmin` class used to enable flat menu editing in the Wagtail admin area to be swapped out for a custom one.
* Added the `WAGTAILMENUS_MAIN_MENUS_MODELADMIN_CLASS` setting to allow the default `ModelAdmin` class used to enable main menu editing in the Wagtail admin area to be swapped out for a custom one.
* Replaced custom app settings module with `django-cogwheels` and removed a lot of the tests that existed to test its workings.
* Moved remaining app settings tests to `wagtailmenus.conf.tests`.

-------------------

* Fix: [329](https://github.com/jazzband/wagtailmenus/issues/329), which prevented level-specific template naming from working as specified in the docs.

-------------------

* Optimised MenuWithMenuItems.get_top_level_items() and AbstractFlatMenu.get_for_site() to use fewer database queries to render menus.
* Configured `sphinxcontrib.spelling` and used to correct spelling errors in docs.
* Updated testing and documentation dependencies.
* Moved `wagtailmenus.constants` and `wagtailmenus.app_settings` into a new `wagtailmenus.conf` app
* Refactored the app settings module to be DRYer and more generic
* Remove `FLAT_MENU_MODEL_CLASS` and `MAIN_MENU_MODEL_CLASS` app settings attributes in favour of using the app settings module's `get_model()` method to return Django models when needed.
* Deprecated the ``WAGTAILMENUS_CHILDREN_MENU_CLASS_PATH`` setting in favour of using just ``WAGTAILMENUS_CHILDREN_MENU_CLASS``.
* Deprecated the ``WAGTAILMENUS_SECTION_MENU_CLASS_PATH`` setting in favour of using just ``WAGTAILMENUS_SECTION_MENU_CLASS``.
* Added Latin American Spanish translations (thanks to José Luis).

------------------

* Added `WAGTAILMENUS_MAIN_MENUS_EDITABLE_IN_WAGTAILADMIN` setting to the 'Main menu' menu item and underlying management functionality to be removed from the Wagtail admin area (thanks to Michael van de Waeter).
* Added `WAGTAILMENUS_FLAT_MENUS_EDITABLE_IN_WAGTAILADMIN` setting to the 'Flat menus' menu item and underlying management functionality to be removed from the Wagtail admin area (thanks to Michael van de Waeter).
* Added the 'sub_menu_templates' option to menu tags to allow sub menu templates to be specified for each level.
* Updated 'get_template_names()' and 'get_sub_menu_template_names()' methods for each class to search for template paths including the level currently being rendered, allowing developers to define level-specific templates in their templates directory, and have wagtailmenus find and use them automatically.