Amethyst-core

- INCOMPATIBLE: Always validate attributes except when using
.direct_set() and .direct_update() methods
- INCOMPATIBLE: Strict validation raises KeyError not ValueError
if passed an absent key name.
- INCOMPATIBLE: Prefix critical methods with amethyst_. Explicitly
document (and test) other methods as overridable by subclasses.
- cached_property: new "delegate" kwarg to delegate storage to an attribute

- documentation updates
- version bump for pypi release

- bugfix: error in using isinstance on bools in amethyst_deflate
- Object .keys(), .values(), .items(), .iteritems() to better impersonate dict()

- Use Attr(OVERRIDE=True) to avoid DuplicateAttributeException
- Add class/attribute name to various error messages to aid in debugging
- Use register_amethyst_type(wrap_encode=False) to skip auto-wrapping
encoded values in a dict (e.g., for plain string-encodable types)
- Attr copies .doc property when creating derived Attrs (e.g., using Attr.strip())
- fromJSON and newFromJSON accept file handles in addition to strings
- Split out functions amethyst_deflate and amethyst_inflate for external serialization
- More documentation

- INCOMPATIBLE: default amethyst_classhint_style is now "flat"
- INCOMPATIBLE: amethyst_strictkeys replaced with more general amethyst_import_strategy
- Attr `default` values immediately apply at object creation
- Object.set() can now take either positional key/value or kwargs
- remove pkgutil.extend_path fallback, use only pkg_resources.declare_namespace

- Initial release