3.0.8

• Merge pull request #154 from dawehner/drupal-6
• Merge pull request #158 from dawehner/test-fixes
• Docs fix for issue #157.
• Merge pull request #147 from lhridley/patch-1
• Merge pull request #151 from pfrenssen/revert-temporary-fix
• Temporary fix for Drupal 8 react/promise issue.
• Merge pull request #145 from jhedstrom/various-cleanup
• Merge pull request #144 from ademarco/d8-user-filed-handling-test
• Merge branch 'ademarco-field-handlers'
• Merge pull request #142 from pfrenssen/ignore-abstract