Merge pull request cwacek#197 from adriangay/importing-abcs-deprecation

fixing Python 3.8 ABC deprecation

Merge pull request cwacek#191 from cwacek/feature/fix-188

Fix 188: Check for ArrayWrapper, then collections.Sequence

Merge pull request cwacek#179 from cwacek/feature/fix-151

Feature: Fixes cwacek#151

Merge pull request cwacek#168 from cwacek/feature/fix-126

bugfix: Add a `__hash__` implementation to ProtocolBase

Merge pull request cwacek#167 from cwacek/feature/fix-165

bugfix: Properly handle attribute deletion. Fixes cwacek#165

Merge pull request cwacek#163 from cwacek/feature/fix-156

bugfix: Fix cwacek#156.

Merge pull request cwacek#158 from kennydo/kedo-more-jsonschema-versions

Test against jsonschema versions 2.3, 2.4, 2.5, 2.6, 3.0

Only deploy with 3.7

Merge pull request cwacek#155 from cwacek/feature/fix-array-refs

bugfix: Make sure array validations happen for references items too

0.3.4

Features

+ Passing named_only=True to build classes will now restrict the
  returned namespace to named classes. Fixes cwacek#141
+ ObjectBuilder can be instantiated with a custom resolver or validator

Bugfixes
+ v4 array validation terms now actually work

Misc
+ pandocfilters is no longer required