1.3.0

[todofixthis]

IMPORTANT: When registering extension filters, please list each filter as its own entry point. The current functionality (loading entire modules) is deprecated and will be removed in v1.4.

See http://filters.readthedocs.io/en/latest/extensions.html#legacy-extensions-loader for more information.

• FilterExtensionRegistry is now a subclass of class_registry.EntryPointClassRegistry.
  • This requires a small change to the way extension filters are registered. See above notice for more information.
• Added filters.macros.FilterMacroType, which acts as a base type for all functions decorated with @filter_macro.
  • FilterMacroType doesn't do anything on its own, but it is useful for identifying a filter macro when paired with an issubclass check (important: use issubclass, not isinstance!).
• Potential fix for filters fails to install using setuptools #23.
• Minor documentation cleanup.